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1.
Front Psychol ; 14: 1239256, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37868597

RESUMO

An important and extensively researched question in the field of reading is whether readers can process multiple words in parallel. An unresolved issue regarding this question is whether the phonological information from foveal and parafoveal words can be processed in parallel, i.e., parallel phonological processing. The present study aims to investigate whether there is parallel phonological processing of Chinese characters. The original and the revised flankers tasks were applied. In both tasks, a foveal target character was presented in isolation in the no-flanker condition, flanked on both sides by a parafoveal homophone in the homophone-flanker condition, and by a non-homophonic character in the unrelated-flanker condition. Participants were instructed to fixate on the target characters and press two keys to indicate whether they knew the target characters (lexical vs. non-lexical). In the original flankers task, the stimuli were presented for 150 ms without a post-mask. In the revised flankers task, we set the stimulus exposure time (duration of the stimuli plus the blank interval between the stimuli and the post-mask) to each participant's lexical decision threshold to prevent participants from processing the target and flanker characters serially. In both tasks, reaction times to the lexical targets were significantly shorter in the homophone-flanker condition than in the unrelated-flanker condition, suggesting parallel phonological processing of Chinese characters. In the revised flankers task, accuracy rates to the lexical targets were significantly lower in the unrelated-flanker condition compared to the homophone-flanker condition, further supporting parallel phonological processing of Chinese characters. Moreover, reaction times to the lexical targets were the shortest in the no-flanker condition in both tasks, reflecting the attention distribution over both the target and flanker characters. The findings of this study provide valuable insights into the parallel processing mechanisms involved in reading.

2.
Ergonomics ; : 1-13, 2023 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-37824713

RESUMO

This study identified the key factors of spousal support that influence the outcomes and willingness of female knowledge workers to work from home (WFH). A questionnaire of 59 items was developed, covering basic personal information, spousal support, work perception, work-life balance, and willingness to WFH: 139 valid responses from female participants were collected and analysed. Exploratory factor analysis revealed six distinct factors of spousal support. Regression analysis found that personal-related emotional support, personal-related instrumental support, work-related emotional support, and work-related instrumental support demonstrated positive correlations with work perception and work-life balance, while family-related instrumental support positively correlated with work-life balance. Personal-related emotional support and personal-related instrumental support positively correlated with the willingness to WFH. Notably, personal-related emotional support exhibited the strongest correlation coefficients for willingness and outcomes. The findings could provide information on how a husband could improve his wife's well-being when WFH.Practitioner summary: A survey was conducted among female knowledge workers to examine the influence of different factors of spousal support on the outcomes and willingness of WFH. The results shed light on how husbands can improve their wives' well-being during WFH, offering practical guidance for supporting spouses in this context.

3.
Percept Mot Skills ; 130(4): 1433-1452, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37235710

RESUMO

This study examined the effects of time pressure, reward, and information involvement on individual fact-checking behavior within a social media platform. We used a four-factor mixed-design experiment to examine fact-checking performances of 144 participants for 36 ambiguous social platform statements, all of which were news statements of social events or of common-sense knowledge collected from the internet and selected through pre-test screening. We measured the participants' total number of fact-checked statements and their judgment accuracy of those statements. We also measured participants' decision time for making judgments, and their judgment confidence levels. Participants' social presence, time pressure, and information involvement were significantly related to the number of statements they fact-checked. Their perceived social presence on a social media platform reduced their fact-checking. Time pressure increased the frequency of fact-checking and weakened the impact of social presence. Participants were less likely to fact-check statements when they had high involvement with the information, due to overconfidence. Statements with high information involvement had longer decision-making times. These findings provide a basis for designing ways to display and push information to increase an individual's awareness of a need to fact-check ambiguous information in a new social media environment.


Assuntos
Mídias Sociais , Humanos , Desinformação , Julgamento , Recompensa
4.
Artigo em Inglês | MEDLINE | ID: mdl-35162266

RESUMO

Risk taking among construction workers is a critical topic in construction safety research. The aim of this study was to empirically investigate how optimism bias and safety climate influence construction worker risk-taking behavior. A survey with a designed questionnaire was conducted to collect data from construction workers. A total of 183 construction workers participated in this study and completed the designed questionnaire. The collected data were subjected to statistical analysis by using structural equation modeling. Results show that optimism bias related to work risks positively influences construction worker risk-taking behavior, whereas safety climate and optimism bias related to hazard perception skills negatively affect the risk-taking behavior. These findings can enrich the literature on construction worker risk-taking behavior from the perspective of optimism bias and safety climate. Practical implications are provided for discouraging construction workers from taking risks at work.


Assuntos
Indústria da Construção , Saúde Ocupacional , Humanos , Cultura Organizacional , Assunção de Riscos , Inquéritos e Questionários
5.
Neuropsychologia ; 165: 108132, 2022 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-34933038

RESUMO

Logographic scripts such as Chinese differ markedly from alphabetic scripts. The time-course of the lexical processing of alphabetic words was widely studied by recording event-related potentials (ERPs), and the results indicated that alphabetic words are rapidly and automatically processed. This study investigated whether there is also rapid and automatic lexical processing of Chinese characters by recording ERPs. High-frequency (HF) characters and orthographically similar low-frequency (LF) characters were pseudo-randomly presented to proficient Chinese readers. The color of half of the characters was blue and the color of the other half was black. In the color decision task, participants were asked to determine the color of each character. In the lexical recognition task, participants were asked to report whether s/he knew each character (the LF characters in this study were very rare characters which were usually not recognized by proficient Chinese readers). In both tasks, the N170 elicited by HF characters peaked earlier than the N170 elicited by LF characters in the right parieto-occipital area (PO8), and the ERPs to HF characters diverged from the ERPs to LF characters around 210-222 ms after the stimulus onset. These results reflected the rapid and automatic lexical processing of Chinese characters. Source analysis results suggested that the left and the right occipitotemporal cortices and the right visual cortex were the neural origins of the early lexical processing of Chinese characters, and the peak activation was in the right visual cortex.


Assuntos
Reconhecimento Visual de Modelos , Leitura , China , Eletroencefalografia/métodos , Potenciais Evocados/fisiologia , Humanos , Reconhecimento Visual de Modelos/fisiologia , Tempo de Reação/fisiologia
6.
Int J Occup Saf Ergon ; 28(4): 2686-2693, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34970947

RESUMO

Head personal protective equipment (HPPE), such as helmets and masks, is protective equipment worn by firefighters to protect their head, neck and face when they are performing tasks. As a wearable device, HPPE significantly affects firefighters' occupational safety and health along with job performance. This study aims to explore the influential factors of HPPE comfort and collect corresponding functional requirements. A semi-structured interview was conducted among five focus groups comprising 31 Chinese firefighters. Through a qualitative analysis of the interview results, eight dimensions of HPPE comfort were proposed: perceived change, movement, attachment, harm, emotion, anxiety, thermal comfort and comfort of vision and hearing. The aspects of weight and size matching are the important reasons behind the comfort problems of the current HPPE. Four aspects of functional requirements were summarized: communication tools, goggles, full-face helmets and lighting. The study findings will provide references for improving HPPE design.


Assuntos
Bombeiros , Humanos , Equipamento de Proteção Individual , Dispositivos de Proteção da Cabeça , Pesquisa Qualitativa , China
7.
Ergonomics ; 61(11): 1519-1529, 2018 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-29856276

RESUMO

This study aimed to determine the touch characteristics during tapping tasks on membrane touch interface and investigate the effects of posture and gender on touch characteristics variables. One hundred participants tapped digits displayed on a membrane touch interface on sitting and standing positions using all fingers of the dominant hand. Touch characteristics measures included average force, contact area and dwell time. Across fingers and postures, males exerted larger force and contact area than females, but similar dwell time. Across genders and postures, thumb exerted the largest force and the force of the other four fingers showed no significant difference. The contact area of the thumb was the largest, whereas that of the little finger was the smallest; the dwell time of the thumb was the longest, whereas that of the middle finger was the shortest. Relationships among finger sizes, gender, posture and touch characteristics were proposed. The findings helped direct membrane touch interface design for digital and numerical control products from hardware and software perspectives. Practitioner Summary: This study measured force, contact area and dwell time in tapping tasks on membrane touch interface and examined effects of gender and posture on force, contact area and dwell time. The findings will direct membrane touch interface design for digital and numerical control products from hardware and software perspectives. Abbreviations: M: mean; SD: standard deviation; ISO: International Organization for Standardization; LCD: liquid crystal display; ANOVA: analysis of variance; ANSI: American National Standards Institute; HFES: Human Factors and Ergonomics Society.


Assuntos
Dedos/fisiologia , Análise e Desempenho de Tarefas , Tato , Adolescente , Adulto , Análise de Variância , Periféricos de Computador , Ergonomia , Feminino , Dedos/anatomia & histologia , Humanos , Masculino , Fenômenos Mecânicos , Fatores Sexuais , Fatores de Tempo , Adulto Jovem
8.
Ergonomics ; 61(2): 273-283, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-28682154

RESUMO

Visual lobe is a useful tool for predicting visual search performance. Up till now, no study has focused on dynamic visual lobe. This study developed a dynamic visual lobe measurement system (DVLMS) that could effectively map dynamic visual lobe and calculate visual lobe shape indices. The effects of display movement velocity on lobe shape indices were examined under four velocity conditions: 0, 4, 8 and 16 deg/s. In general, with the increase of display movement velocity, visual lobe area and perimeter became smaller, whereas lobe shape roundness, boundary smoothness, symmetry and regularity deteriorated. The elongation index was not affected by velocity. Regression analyses indicated that display movement velocity was important in determining dynamic visual lobe shape indices. Dynamic visual lobe provides another option for better understanding dynamic vision, in addition to dynamic visual acuity. Findings of this study can provide guidelines for analysing and designing dynamic visual tasks. Practitioner Summary: Dynamic visual lobe is important in reflecting the visual ability of searching for a moving target. We developed a dynamic visual lobe measurement system (DVLMS) and examined display movement velocity's effects on lobe shape. Findings revealed that velocity was a key factor affecting dynamic visual lobe shape indices.


Assuntos
Reconhecimento Visual de Modelos , Estimulação Luminosa/métodos , Campos Visuais , Percepção Visual , Humanos , Reprodutibilidade dos Testes , Análise e Desempenho de Tarefas , Adulto Jovem
9.
Sci Rep ; 7(1): 14921, 2017 11 02.
Artigo em Inglês | MEDLINE | ID: mdl-29097713

RESUMO

The effect of motion on visual search has been extensively investigated, but that of uniform linear motion of display on search performance for tasks with different target-distractor shape representations has been rarely explored. The present study conducted three visual search experiments. In Experiments 1 and 2, participants finished two search tasks that differed in target-distractor shape representations under static and dynamic conditions. Two tasks with clear and blurred stimuli were performed in Experiment 3. The experiments revealed that target-distractor shape representation modulated the effect of motion on visual search performance. For tasks with low target-distractor shape similarity, motion negatively affected search performance, which was consistent with previous studies. However, for tasks with high target-distractor shape similarity, if the target differed from distractors in that a gap with a linear contour was added to the target, and the corresponding part of distractors had a curved contour, motion positively influenced search performance. Motion blur contributed to the performance enhancement under dynamic conditions. The findings are useful for understanding the influence of target-distractor shape representation on dynamic visual search performance when display had uniform linear motion.


Assuntos
Percepção de Forma , Percepção Visual , Adolescente , Adulto , Atenção , Humanos , Movimento (Física) , Movimentos Sacádicos , Adulto Jovem
10.
Sci Rep ; 7(1): 15073, 2017 11 08.
Artigo em Inglês | MEDLINE | ID: mdl-29118377

RESUMO

Working with co-actors is a common work-organization mode. Whether the presence of opposite-sex co-actors (OCs) can induce social facilitation effect and how an actor's performance is influenced by the gender composition of co-actors remain unknown. The present study aims to examine the influence of the gender composition of co-actors on the intensity of the social facilitation effect. In Experiment 1, participants performed visual search tasks alone and in six co-action conditions with varying gender compositions. In Experiment 2, the participants performed modular arithmetic tasks in three conditions with electroencephalogram activity recorded and salivary cortisol measured: alone, with a same-sex co-actor (SC), and with an OC. Results indicated that the social facilitation effect was stronger in the presence of OCs than in the presence of only SCs. The intensities of social facilitation effect resulting from the varying gender composition of co-actors were obtained and compared. A participant's power of alpha band was lower, whereas power of beta band and normalised cortisol level were higher in the presence of an OC than in the presence of an SC. These findings provide insights into the influencing mechanisms of gender composition on the intensity of the social facilitation effect in the co-action condition.


Assuntos
Relações Interpessoais , Desempenho Psicomotor/fisiologia , Facilitação Social , Interface Usuário-Computador , Adolescente , Adulto , Encéfalo/fisiologia , Eletroencefalografia , Feminino , Humanos , Masculino , Tempo de Reação/fisiologia , Fatores Sexuais , Adulto Jovem
11.
Ergonomics ; 60(12): 1667-1681, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28612679

RESUMO

This study employed an eye-tracking technique to investigate the influence of social presence on eye movements in visual search tasks. A total of 20 male subjects performed visual search tasks in a 2 (target presence: present vs. absent) × 2 (task complexity: complex vs. simple) × 2 (social presence: alone vs. a human audience) within-subject experiment. Results indicated that the presence of an audience could evoke a social facilitation effect on response time in visual search tasks. Compared with working alone, the participants made fewer and shorter fixations, larger saccades and shorter scan path in simple search tasks and more and longer fixations, smaller saccades and longer scan path in complex search tasks when working with an audience. The saccade velocity and pupil diameter in the audience-present condition were larger than those in the working-alone condition. No significant change in target fixation number was observed between two social presence conditions. Practitioner Summary: This study employed an eye-tracking technique to examine the influence of social presence on eye movements in visual search tasks. Results clarified the variation mechanism and characteristics of oculomotor scanning induced by social presence in visual search.


Assuntos
Movimentos Oculares , Facilitação Social , Análise e Desempenho de Tarefas , Adulto , Medições dos Movimentos Oculares , Fixação Ocular , Humanos , Masculino , Tempo de Reação , Movimentos Sacádicos , Percepção Visual , Adulto Jovem
12.
Ergonomics ; 60(5): 680-691, 2017 May.
Artigo em Inglês | MEDLINE | ID: mdl-27258596

RESUMO

This study identified the risk factors influencing visual fatigue in baggage X-ray security screeners and estimated the strength of correlations between those factors and visual fatigue using structural equation modelling approach. Two hundred and five X-ray security screeners participated in a questionnaire survey. The result showed that satisfaction with the VDT's physical features and the work environment conditions were negatively correlated with the intensity of visual fatigue, whereas job stress and job burnout had direct positive influences. The path coefficient between the image quality of VDT and visual fatigue was not significant. The total effects of job burnout, job stress, the VDT's physical features and the work environment conditions on visual fatigue were 0.471, 0.469, -0.268 and -0.251 respectively. These findings indicated that both extrinsic factors relating to VDT and workplace environment and psychological factors including job burnout and job stress should be considered in the workplace design and work organisation of security screening tasks to reduce screeners' visual fatigue. Practitioner Summary: This study identified the risk factors influencing visual fatigue in baggage X-ray security screeners and estimated the strength of correlations between those factors and visual fatigue. The findings were of great importance to the workplace design and the work organisation of security screening tasks to reduce screeners' visual fatigue.


Assuntos
Astenopia/etiologia , Esgotamento Profissional/psicologia , Modelos Teóricos , Meios de Transporte , Local de Trabalho , Adolescente , Adulto , Terminais de Computador/normas , Feminino , Humanos , Satisfação no Emprego , Masculino , Saúde Ocupacional , Fatores de Risco , Medidas de Segurança , Inquéritos e Questionários , Raios X , Adulto Jovem
13.
Work ; 52(4): 911-9, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26409398

RESUMO

BACKGROUND: Manual materials handling (MMH) tasks are common. They are considered major contributors of musculoskeletal injuries and are the sources of financial burden for industries in terms of lost work days and worker compensation costs. One-handed carrying is common and could result in arm fatigue. OBJECTIVE: The purpose of this study was to establish predictive models for one-handed carrying strength considering weight handed and handedness conditions. METHODS: Twenty male subjects were recruited for the study. The subject carried a weight of 6 or 12 kg using either dominant or non-dominant hand lasting a time period of 0, 0.5, 1, 1.5, 2, 2.5, 3, 3.5, or 4 minutes. RESULTS: The results showed that handedness (p <  0.0001), weight (p <  0.05), and time period (p <  0.0001) were all significant factors affecting single arm carrying strength. Predictive models of single arm carrying strength were established under handedness and weight conditions. The MADs of these models ranged from 0.39 to 2.19 kgf. CONCLUSION: The exponential function based predictive models may be adopted to describe the single arm carrying strength with reasonable predictive errors. The trend of the carrying strength after carrying a load for a certain period may be employed to describe muscular fatigue for sustained carrying tasks.


Assuntos
Remoção , Modelos Teóricos , Fadiga Muscular , Força Muscular , Músculo Esquelético/fisiopatologia , Braço , Lateralidade Funcional/fisiologia , Humanos , Masculino , Suporte de Carga/fisiologia , Adulto Jovem
14.
Ergonomics ; 58(6): 857-65, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25554925

RESUMO

This study investigated whether the mere presence of a human audience would evoke a social facilitation effect in baggage X-ray security screening tasks. A 2 (target presence: present vs. absent) ×  2 (task complexity: simple vs. complex) ×  2 (social presence: alone vs. human audience) within-subject experiment simulating a real baggage screening task was conducted. This experiment included 20 male participants. The participants' search performance in this task was recorded. The results showed that the presence of a human audience speeded up responses in simple tasks and slowed down responses in complex tasks. However, the social facilitation effect produced by the presence of a human audience had no effect on response accuracy. These findings suggested that the complexity of screening tasks should be considered when designing work organisation modes for security screening tasks. Practitioner summary: This study investigated whether the presence of a human audience could evoke a social facilitation effect in baggage X-ray security screening tasks. An experimental simulation was conducted. The results showed that the presence of a human audience facilitated the search performance of simple tasks and inhibited the performance of complex tasks.


Assuntos
Facilitação Social , Análise e Desempenho de Tarefas , Trabalho , Adolescente , Humanos , Masculino , Medidas de Segurança , Adulto Jovem
15.
Work ; 50(4): 649-57, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-24448018

RESUMO

BACKGROUND: Slips and falls contribute to occupational injuries and fatalities globally. Both floor slipperiness and floor roughness affect the occurrence of slipping and falling. Investigations on fall-related phenomena are important for the safety and health of workers. OBJECTIVE: The purposes of this study were to: compare the perceived floor slipperiness before and after walking on the floor; compare the perceived floor slipperiness with and without shoes for males and females; discuss the perceived floor roughness based on barefoot walking; and establish regression models to describe the relationship between perceived floor slipperiness and actual friction of the floors. METHODS: Male and female subjects walked on 3 m walkways with or without shoes. The perceived floor slipperiness ratings both before and after their walk were collected. RESULTS: The perceived floor slipperiness both before and after walking were significantly affected by both floor and surface conditions. Gender, floor, surface, and footwear conditions were all significant factors affecting the adjustment of perceived floor slipperiness. The subjects made more adjustment on perceived floor slipperiness rating when they had shoes on than when they were barefooted. CONCLUSION: Regression models were established to describe the relationship between perceived floor slipperiness and floor coefficient of friction. These models may be used to estimate perceived floor slipperiness, or in reverse, the coefficient of friction of the floor, so as to prevent slipping and falling in workplaces.


Assuntos
Pisos e Cobertura de Pisos , Fricção , Marcha/fisiologia , Saúde Ocupacional , Percepção , Feminino , Humanos , Masculino , Fatores Sexuais , Sapatos , Propriedades de Superfície , Caminhada , Adulto Jovem
16.
Int J Occup Saf Ergon ; 20(3): 437-45, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25189748

RESUMO

This study used the psychophysical approach to investigate the impact of tempo and volume of background music on the maximum acceptable weight of lift (MAWL), heart rate (HR) and rating of perceived exertion (RPE) of participants engaged in lifting. Ten male college students participated in this study. They lifted a box from the floor, walked 1-2 steps as required, placed the box on a table and walked back twice per minute. The results showed that the tempo of music had a significant effect on both MAWL and HR. Fast tempo background music resulted in higher MAWL and HR values than those resulting from slow tempo music. The effects of both the tempo and volume on the RPE were insignificant. The results of this study suggest fast tempo background music may be used in manual materials handling tasks to increase performance without increasing perceived exertion because of its ergogenic effect on human psychology and physiology.


Assuntos
Frequência Cardíaca/fisiologia , Remoção , Música , Percepção , Caminhada/fisiologia , Suporte de Carga/fisiologia , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Saúde Ocupacional , Esforço Físico/fisiologia
17.
Ergonomics ; 57(9): 1300-14, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24874282

RESUMO

Visual lobe shape plays an important role in visual search performance, but little is known about the age-related changes in visual lobe shape. The age-related changes in visual lobe shape characteristics and their relationships to visual search performance were investigated in this study. A total of 96 participants aged 15-64 years participated in this study. Their visual lobes were mapped on a uniform 2-D test field composed of 24 regularly spaced meridians passing through the centre of the visual field, and their search performances were also measured. The results showed that in general, age significantly affected visual lobe size, visual lobe shape and search time. As age increased, the visual lobe size decreased; in addition, the roundness, boundary smoothness, symmetry and regularity of the visual lobe deteriorated, and the search time increased. Moreover, significant correlations between visual lobe shape, search time and age were found. Regression analyses indicated that age was important in determining visual lobe shape and search time, suggesting that age differences should be considered when predicting search time and when designing tasks and products that involve visual search in our daily lives and work. PRACTITIONER SUMMARY: Age-related changes in visual lobe shape characteristics and their relationships to visual search performance were investigated in this study. The results help to explain how tasks and products involving visual search in our daily lives and work should be designed for target audiences of different ages.


Assuntos
Envelhecimento/fisiologia , Reconhecimento Visual de Modelos , Tempo de Reação , Campos Visuais , Percepção Visual , Adolescente , Adulto , Fatores Etários , Encéfalo/anatomia & histologia , Fixação Ocular , Humanos , Pessoa de Meia-Idade , Análise e Desempenho de Tarefas , Adulto Jovem
18.
Int J Inj Contr Saf Promot ; 20(3): 245-53, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22591543

RESUMO

Investigation of floor slipperiness is critical in studying the risk of slips and falls. This research conducted friction measurements and employee survey on floor slipperiness in a student cafeteria in a university in China in order to study the correlation between the two types of floor slipperiness measure. It was found that the fryer area in kitchen 1 and the meat defrost sink in kitchen 2 had significantly the lowest coefficient of friction (COF) values among all areas in the same kitchen. The results showed that the levels of friction on the floors in different areas in each kitchen were significantly different. Employee perceptions of floor slipperiness among areas were also significantly different. The level of friction and employee perception of floor slipperiness was highly correlated (ρ = 0.87). This implies a good agreement between the two measures. A linear regression model was established to describe the relationship between the perceived floor slipperiness and the measured COF. The model was significant at p < 0.0001 with an R (2) of 0.59.


Assuntos
Acidentes por Quedas , Acidentes de Trabalho , Pisos e Cobertura de Pisos , Serviços de Alimentação , Universidades , Acidentes por Quedas/prevenção & controle , Acidentes de Trabalho/prevenção & controle , Adulto , China , Feminino , Fricção , Humanos , Masculino , Óleos , Percepção , Medição de Risco , Água
19.
Stat Med ; 31(13): 1369-79, 2012 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-22344706

RESUMO

The accelerated failure time model is frequently used in survival analysis because of its direct physical interpretation. Semiparametric inference methods have been extensively investigated for this model. However, the accelerated failure time model and the existing inference methods assume homogeneity of the survival data after taking log-transformation. This assumption is not always appropriate because heterogeneous data are often encountered in practice. In dealing with this heterogeneity, Yu, Yu, and Liu proposed a parametric quasi-likelihood method by assuming a known variance function, which may not be realistic for real data. In this paper, we extend the parametric quasi-likelihood method to semiparametric via relaxing its assumption and approximating the unknown variance function by using fractional polynomials approach. Simulations show that this novel extension performs superior to other methods in statistical properties of unbiasedness, efficiency, and correct coverage probability in finite samples. An application to real data set in primary biliary cirrhosis demonstrates the applicability of this new methodology.


Assuntos
Funções Verossimilhança , Análise de Sobrevida , Análise de Variância , Simulação por Computador/estatística & dados numéricos , Humanos , Cirrose Hepática Biliar/epidemiologia
20.
Appl Ergon ; 42(6): 929-33, 2011 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-21439549

RESUMO

The Borg CR-10 scale has been used to quantify the perception of physical exertion. An experiment was conducted to test the grip force of males on four levels of the CR-10 scale under experimental conditions. It was found that the subjects applied higher grip forces than they perceived at levels 2, 5, and 7 on the scale. The grip forces between dominant and non-dominant hands at low CR-10 levels were negligible. The grip forces were significantly different between the two hands at level 10. Similar results were found for the postural conditions. A follow-up experiment was conducted to estimate the subjective rating when applying a pre-determined grip force under the same conditions. Regression models were established to link the relationship between the subjective rating and hand force. The estimated ratings were lower than those actual values under all the tested conditions, even though the models have high R² values.


Assuntos
Lateralidade Funcional/fisiologia , Força da Mão/fisiologia , Postura/fisiologia , Mãos/fisiologia , Humanos , Masculino , Força Muscular/fisiologia , Dinamômetro de Força Muscular , Adulto Jovem
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