862 resultados para subjective and objective video quality assessment
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Este trabalho teve como objetivo avaliar as características bioquímicas da carne de bubalinos Mediterrâneo terminados em confinamento e abatidos em diferentes pesos. Foram utilizados 28 bubalinos Mediterrâneo jovens, com idade de 9 meses, e peso vivo médio inicial de 240kg. Os animais foram alimentados com ração total à vontade em regime de confinamento até atingirem pesos de abate de 450, 480, 510 e 540kg de peso vivo (tratamentos). Os valores de pH e temperatura dos músculos Longissimus dorsi e Bíceps femoris foram coletados a intervalos de duas horas durante 24 horas após o abate. Determinou-se a cor da carne pelos métodos subjetivo e objetivo. Não houve efeito de interação entre tratamento e tempo de coleta. Não houve diferença significativa entre os tratamentos em relação ao pH e à temperatura nos dois músculos estudados (Longissimus dorsi e Bíceps femoris) durante o processo de resfriamento das carcaças. Os valores médios de pH inicial e pH final dos músculos Longissimus dorsi e Bíceps femoris foram de 6,6 e 5,4; e de 6,3 e 5,5, respectivamente. Os valores médios de temperatura inicial e final dos músculos Longissimus dorsi e Bíceps femoris foram 39,7°C e 4,1°C; 40,4°C e 7,0°C, respectivamente. Quanto à cor da carne, pelo método subjetivo, não houve diferença significativa entre os tratamentos estudados, obtendo-se a média geral de 3,41 pontos. em relação à cor da carne pelo método objetivo, não houve diferença significativa entre os tratamentos estudados. Os valores médios encontrados foram : L*= 35,16; a*=12,43 e b*=5,29. A carne bubalina, apesar de se apresentar mais escura que a carne bovina, não traz prejuízos quanto ao aspecto visual para o consumidor.
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O objetivo do presente trabalho é investigar a temática da razão subjetiva e objetiva especialmente através de uma leitura minuciosa da obra De Ratione, una, universalli, infinita. Trata-se de um escrito juvenil do pensador, mas nele já podemos vislumbrar os futuros desdobramento de suas teses futuras. Com efeito, o intuito é investigar aqui seus posicionamentos primitivos, buscando extrair deles conseqüências para o próprio filosofar posterior do pensador, bem como a inserção de tais teses no contexto filosófico. _________________________________________________________________________________ ABSTRACT
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The goal of this work is to develop a method to objectively compare the performance of a digital and a screen-film mammography system in terms of image quality. The method takes into account the dynamic range of the image detector, the detection of high and low contrast structures, the visualisation of the images and the observer response. A test object, designed to represent a compressed breast, was constructed from various tissue equivalent materials ranging from purely adipose to purely glandular composition. Different areas within the test object permitted the evaluation of low and high contrast detection, spatial resolution and image noise. All the images (digital and conventional) were captured using a CCD camera to include the visualisation process in the image quality assessment. A mathematical model observer (non-prewhitening matched filter), that calculates the detectability of high and low contrast structures using spatial resolution, noise and contrast, was used to compare the two technologies. Our results show that for a given patient dose, the detection of high and low contrast structures is significantly better for the digital system than for the conventional screen-film system studied. The method of using a test object with a large tissue composition range combined with a camera to compare conventional and digital imaging modalities can be applied to other radiological imaging techniques. In particular it could be used to optimise the process of radiographic reading of soft copy images.
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This work shows the objective results of the acoustic quality of the Compañia de Jesús Church in Cordoba, Argentina. The acoustics of this Temple, built by the Orden Jesuita (Jesuit Order) two centuries ago and declared a World Heritage Site by UNESCO in 2000, is currently considered optimal by musicians as well as general public. In the second half of XVI century, with the Catholic reform, the need for improved speech intelligibility was given priority, being the Jesuit one of the orders that gave most importance to the construction of their temples. This church has constructive and spatial characteristics consistent with those needs. With the purpose of carrying out the acoustic assessment of the precincts, a work methodology that allowed comparing the results obtained from objective measures was developed by means of implementation of field measurements and space modeling, with subjective appreciation results, by developing surveys, with the aim of characterizing acoustically the sound space. This paper shows the comparison between the subjective results and objective criteria, which allowed important conclusions on the acoustic behavior of the temple to be obtained. In this way interesting data were obtained in relation to the subjective response of the acoustics of the church.
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Esta tesis presenta un estudio exhaustivo sobre la evaluación de la calidad de experiencia (QoE, del inglés Quality of Experience) percibida por los usuarios de sistemas de vídeo 3D, analizando el impacto de los efectos introducidos por todos los elementos de la cadena de procesamiento de vídeo 3D. Por lo tanto, se presentan varias pruebas de evaluación subjetiva específicamente diseñadas para evaluar los sistemas considerados, teniendo en cuenta todos los factores perceptuales relacionados con la experiencia visual tridimensional, tales como la percepción de profundidad y la molestia visual. Concretamente, se describe un test subjetivo basado en la evaluación de degradaciones típicas que pueden aparecer en el proceso de creación de contenidos de vídeo 3D, por ejemplo debidas a calibraciones incorrectas de las cámaras o a algoritmos de procesamiento de la señal de vídeo (p. ej., conversión de 2D a 3D). Además, se presenta el proceso de generación de una base de datos de vídeos estereoscópicos de alta calidad, disponible gratuitamente para la comunidad investigadora y que ha sido utilizada ampliamente en diferentes trabajos relacionados con vídeo 3D. Asimismo, se presenta otro estudio subjetivo, realizado entre varios laboratorios, con el que se analiza el impacto de degradaciones causadas por la codificación de vídeo, así como diversos formatos de representación de vídeo 3D. Igualmente, se describen tres pruebas subjetivas centradas en el estudio de posibles efectos causados por la transmisión de vídeo 3D a través de redes de televisión sobre IP (IPTV, del inglés Internet Protocol Television) y de sistemas de streaming adaptativo de vídeo. Para estos casos, se ha propuesto una innovadora metodología de evaluación subjetiva de calidad vídeo, denominada Content-Immersive Evaluation of Transmission Impairments (CIETI), diseñada específicamente para evaluar eventos de transmisión simulando condiciones realistas de visualización de vídeo en ámbitos domésticos, con el fin de obtener conclusiones más representativas sobre la experiencia visual de los usuarios finales. Finalmente, se exponen dos experimentos subjetivos comparando varias tecnologías actuales de televisores 3D disponibles en el mercado de consumo y evaluando factores perceptuales de sistemas Super Multiview Video (SMV), previstos a ser la tecnología futura de televisores 3D de consumo, gracias a una prometedora visualización de contenido 3D sin necesidad de gafas específicas. El trabajo presentado en esta tesis ha permitido entender los factores perceptuales y técnicos relacionados con el procesamiento y visualización de contenidos de vídeo 3D, que pueden ser de utilidad en el desarrollo de nuevas tecnologías y técnicas de evaluación de la QoE, tanto metodologías subjetivas como métricas objetivas. ABSTRACT This thesis presents a comprehensive study of the evaluation of the Quality of Experience (QoE) perceived by the users of 3D video systems, analyzing the impact of effects introduced by all the elements of the 3D video processing chain. Therefore, various subjective assessment tests are presented, particularly designed to evaluate the systems under consideration, and taking into account all the perceptual factors related to the 3D visual experience, such as depth perception and visual discomfort. In particular, a subjective test is presented, based on evaluating typical degradations that may appear during the content creation, for instance due to incorrect camera calibration or video processing algorithms (e.g., 2D to 3D conversion). Moreover, the process of generation of a high-quality dataset of 3D stereoscopic videos is described, which is freely available for the research community, and has been already widely used in different works related with 3D video. In addition, another inter-laboratory subjective study is presented analyzing the impact of coding impairments and representation formats of stereoscopic video. Also, three subjective tests are presented studying the effects of transmission events that take place in Internet Protocol Television (IPTV) networks and adaptive streaming scenarios for 3D video. For these cases, a novel subjective evaluation methodology, called Content-Immersive Evaluation of Transmission Impairments (CIETI), was proposed, which was especially designed to evaluate transmission events simulating realistic home-viewing conditions, to obtain more representative conclusions about the visual experience of the end users. Finally, two subjective experiments are exposed comparing various current 3D displays available in the consumer market, and evaluating perceptual factors of Super Multiview Video (SMV) systems, expected to be the future technology for consumer 3D displays thanks to a promising visualization of 3D content without specific glasses. The work presented in this thesis has allowed to understand perceptual and technical factors related to the processing and visualization of 3D video content, which may be useful in the development of new technologies and approaches for QoE evaluation, both subjective methodologies and objective metrics.
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OBJECTIVE: To investigate the relevance of subjective criteria adopted by a psychiatry and psychology consultation-liaison service, and their suitability in the evaluation of case registries and objective results. METHODS: Semi-structured interviews were conducted and all supervisors of the university hospital service were interviewed. Routinely collected case registries were also reviewed. Standardized assessment with content analysis for each category was carried out. RESULTS: The results showed distortions in the adopted service focus (doctor-patient relationship) and consultant requests. This focus is more on consulting physician-oriented interventions than on patients. DISCUSSION: Evaluation of the relevance of service criteria could help promoting quality assessment of the services provided, mainly when objective criteria have not yet been established to assure their suitability.
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Objective: To assess the indoor environment of two different types of dental practices regarding VOCs, PM2.5, and ultrafine particulate concentrations and examine the relationship between specific dental activities and contaminant levels. Method: The indoor environments of two selected dental settings (private practice and community health center) will were assessed in regards to VOCs, PM 2.5, and ultrafine particulate concentrations, as well as other indoor air quality parameters (CO2, CO, temperature, and relative humidity). The sampling duration was four working days for each dental practice. Continuous monitoring and integrated sampling methods were used and number of occupants, frequency, type, and duration of dental procedures or activities recorded. Measurements were compared to indoor air quality standards and guidelines. Results: The private practice had higher CO2, CO, and most VOC concentrations than the community health center, but the community health center had higher PM2.5 and ultrafine PM concentrations. Concentrations of p-dichlorobenzene and PM2.5 exceeded some guidelines. Outdoor concentrations greatly influenced the indoor concentration. There were no significant differences in contaminant levels between the operatory and general area. Indoor concentrations during the working period were not always consistently higher than during the nonworking period. Peaks in particulate matter concentration occurred during root canal and composite procedures.^
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Background The aim of this study is to present face, content, and constructs validity of the endoscopic orthogonal video system (EndoViS) training system and determines its efficiency as a training and objective assessment tool of the surgeons’ psychomotor skills. Methods Thirty-five surgeons and medical students participated in this study: 11 medical students, 19 residents, and 5 experts. All participants performed four basic skill tasks using conventional laparoscopic instruments and EndoViS training system. Subsequently, participants filled out a questionnaire regarding the design, realism, overall functionality, and its capabilities to train hand–eye coordination and depth perception, rated on a 5-point Likert scale. Motion data of the instruments were obtained by means of two webcams built into a laparoscopic physical trainer. To identify the surgical instruments in the images, colored markers were placed in each instrument. Thirteen motion-related metrics were used to assess laparoscopic performance of the participants. Statistical analysis of performance was made between novice, intermediate, and expert groups. Internal consistency of all metrics was analyzed with Cronbach’s α test. Results Overall scores about features of the EndoViS system were positives. Participants agreed with the usefulness of tasks and the training capacities of EndoViS system (score >4). Results presented significant differences in the execution of three skill tasks performed by participants. Seven metrics showed construct validity for assessment of performance with high consistency levels. Conclusions EndoViS training system has been successfully validated. Results showed that EndoViS was able to differentiate between participants of varying laparoscopic experience. This simulator is a useful and effective tool to objectively assess laparoscopic psychomotor skills of the surgeons.
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Digital still cameras capable of filming short video clips are readily available, but the quality of these recordings for telemedicine has not been reported. We performed a blinded study using four commonly available digital cameras. A simulated patient with a hemiplegic gait pattern was filmed by the same videographer in an identical, brightly lit indoor setting. Six neurologists viewed the blinded video clips on their PC and comparisons were made between cameras, between video clips recorded with and without a tripod, and between video clips filmed on high- or low-quality settings. Use of a tripod had a smaller effect than expected, while images taken on a high-quality setting were strongly preferred to those taken on a low-quality setting. Although there was some variability in video quality between selected cameras, all were of sufficient quality to identify physical signs such as gait and tremor. Adequate-quality video clips of movement disorders can be produced with low-cost cameras and transmitted by email for teleneurology purposes.
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Computed tomography (CT) is a valuable technology to the healthcare enterprise as evidenced by the more than 70 million CT exams performed every year. As a result, CT has become the largest contributor to population doses amongst all medical imaging modalities that utilize man-made ionizing radiation. Acknowledging the fact that ionizing radiation poses a health risk, there exists the need to strike a balance between diagnostic benefit and radiation dose. Thus, to ensure that CT scanners are optimally used in the clinic, an understanding and characterization of image quality and radiation dose are essential.
The state-of-the-art in both image quality characterization and radiation dose estimation in CT are dependent on phantom based measurements reflective of systems and protocols. For image quality characterization, measurements are performed on inserts imbedded in static phantoms and the results are ascribed to clinical CT images. However, the key objective for image quality assessment should be its quantification in clinical images; that is the only characterization of image quality that clinically matters as it is most directly related to the actual quality of clinical images. Moreover, for dose estimation, phantom based dose metrics, such as CT dose index (CTDI) and size specific dose estimates (SSDE), are measured by the scanner and referenced as an indicator for radiation exposure. However, CTDI and SSDE are surrogates for dose, rather than dose per-se.
Currently there are several software packages that track the CTDI and SSDE associated with individual CT examinations. This is primarily the result of two causes. The first is due to bureaucracies and governments pressuring clinics and hospitals to monitor the radiation exposure to individuals in our society. The second is due to the personal concerns of patients who are curious about the health risks associated with the ionizing radiation exposure they receive as a result of their diagnostic procedures.
An idea that resonates with clinical imaging physicists is that patients come to the clinic to acquire quality images so they can receive a proper diagnosis, not to be exposed to ionizing radiation. Thus, while it is important to monitor the dose to patients undergoing CT examinations, it is equally, if not more important to monitor the image quality of the clinical images generated by the CT scanners throughout the hospital.
The purposes of the work presented in this thesis are threefold: (1) to develop and validate a fully automated technique to measure spatial resolution in clinical CT images, (2) to develop and validate a fully automated technique to measure image contrast in clinical CT images, and (3) to develop a fully automated technique to estimate radiation dose (not surrogates for dose) from a variety of clinical CT protocols.
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Measuring the quality of a b-learning environment is critical to determine the success of a b-learning course. Several initiatives have been recently conducted on benchmarking and quality in e-learning. Despite these efforts in defining and examining quality issues concerning online courses, a defining instrument to evaluate quality is one of the key challenges for blended learning, since it incorporates both traditional and online instruction methods. For this paper, six frameworks for quality assessment of technological enhanced learning were examined and compared regarding similarities and differences. These frameworks aim at the same global objective: the quality of e-learning environment/products. They present different perspectives but also many common issues. Some of them are more specific and related to the course and other are more global and related to institutional aspects. In this work we collected and arrange all the quality criteria identified in order to get a more complete framework and determine if it fits our b-learning environment. We also included elements related to our own b-learning research and experience, acquired during more than 10 years of experience. As a result we have create a new quality reference with a set of dimensions and criteria that should be taken into account when you are analyzing, designing, developing, implementing and evaluating a b-learning environment. Besides these perspectives on what to do when you are developing a b-learning environment we have also included pedagogical issues in order to give directions on how to do it to reach the success of the learning. The information, concepts and procedures here presented give support to teachers and instructors, which intend to validate the quality of their blended learning courses.
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RESUMO: Objetivo Avaliar a qualidade dos serviços de saúde mental e a situação dos direitos humanos no Hospital de Saúde Mental de Kabul (KMHH) e fornecer recomendações para o desenvolvimento de um plano de melhoria, actualização e revisão da Política, Estratégia e Plano Nacionais de Saúde Mental,. Métodos A avaliação foi realizada em Janeiro de 2015 no KMHH e na Burn Ward do Hospital Terciário de Isteqlal por uma equipa multidisciplinar usando Qualidade Direitos Tool Kit da OMS. Antes da avaliação, o protocolo foi aprovado pelo Institutional Review Board e obtido o consentimento informado de cada entrevistado. Realizaram-se entrevistas com 16 utentes do serviço, 17 funcionários do hospital e 7 familiares, além da revisão de documentos e da observação das unidades de internamento do KMHH e das interações interpessoais entre funcionários do hospital e utentes do serviço. A comissão de avaliação reviu também a documentação e observou a Unidade de Queimados do Hospital Terciário de Isteqlal, a fim de avaliar e comparar a paridade entre as duas instalações. Após a avaliação, todos os membros da comissão se reuniram e puseram em conjunto todas as conclusões num relatório final. Resultados Encontrámos algumas lacunas graves no nível de prestação de serviços e no respeito pelos direitos humanos dos utentes dos serviços e dos seus familiares. Uma série de políticas, diretrizes e procedimentos relacionados com os direitos humanos dos pacientes estavam ausentes. O ambiente terapêutico e o padrão de vida eram inadequados, existia má qualidade do atendimento e dos serviços prestados, os utilizadores enfrentavam violações do direito ao exercício da capacidade legal e da liberdade pessoal, eram quimica e fisicamente (uso de correntes) contidos e expostos a abusos verbais, físicos e emocionais, e havia grande ênfase no tratamento institucional. Todos estes aspectos foram considerados como extensa violação dos direitos humanos dos utentes de serviço do KMHH. Conclusão Os serviços disponíveis para utentes dos serviços de saúde mental apresentam alguns problemas devido à desconfiança e falta de consciencialização sobre os direitos das pessoas com doença mental e precisam ser alterados de forma positiva. A Lei de Saúde Mental existente difere muito das recomendações da Convenção sobre os Direitos das Pessoas com Incapacidades (CRPD) e requer revisão e adaptação de acordo com esta Convenção. -------------------------------- ABSTRACT: Objective To assess the quality of mental health services and human rights condition in the Kabul Mental Health Hospital (KMHH) and provide recommendations for development of an improvement plan and to update and revise the National Mental Health Policy, Strategy and Plan. Methods The assessment was conducted in January 2015 in the KMHH and the Burn Ward of Isteqlal Tertiary Hospital by a multidisciplinary team using WHO Quality Rights Tool Kit. Before the assessment, Institutional Review Board approval and informed consent from each interviewee were obtained. Interviews were conducted with 16 service users, 17 hospital staffs and 7 family members in addition to documents review and observation of inpatient units of KMHH plus interpersonal interactions between hospital staff and service users. The assessment committee reviewed the documentation and observed the Burn Ward of Isteqlal Tertiary hospital in order to measure and compare parity between the two facilities. After the assessment, all committee members gathered and synchronized all findings into a final report. Results There were some serious gaps on service provision level and respecting human rights of service users and their family members. A series of policies, guidelines and procedures related to patients’ human rights were absent. Inadequate treatment environment and standard of living, poor quality of care and services, violations of the right to exercise legal capacity and personal liberty, being chemically and physically (e.g. chain) restrained, being exposed to verbal, physical and emotional abuse, and emphasis on institutional treatment were all extensive human rights violation that service users were experiencing in KMHH. Conclusion The available services for mental health service users are questionable due to mistrust and lack of awareness about rights of people with disabilities and need to be positively changed. Existing Mental Health Act has a large number of disparities with the CRPD and requires revision and adaptation in accordance to CRPD.
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PURPOSE: Iterative algorithms introduce new challenges in the field of image quality assessment. The purpose of this study is to use a mathematical model to evaluate objectively the low contrast detectability in CT. MATERIALS AND METHODS: A QRM 401 phantom containing 5 and 8 mm diameter spheres with a contrast level of 10 and 20 HU was used. The images were acquired at 120 kV with CTDIvol equal to 5, 10, 15, 20 mGy and reconstructed using the filtered back-projection (FBP), adaptive statistical iterative reconstruction 50% (ASIR 50%) and model-based iterative reconstruction (MBIR) algorithms. The model observer used is the Channelized Hotelling Observer (CHO). The channels are dense difference of Gaussian channels (D-DOG). The CHO performances were compared to the outcomes of six human observers having performed four alternative forced choice (4-AFC) tests. RESULTS: For the same CTDIvol level and according to CHO model, the MBIR algorithm gives the higher detectability index. The outcomes of human observers and results of CHO are highly correlated whatever the dose levels, the signals considered and the algorithms used when some noise is added to the CHO model. The Pearson coefficient between the human observers and the CHO is 0.93 for FBP and 0.98 for MBIR. CONCLUSION: The human observers' performances can be predicted by the CHO model. This opens the way for proposing, in parallel to the standard dose report, the level of low contrast detectability expected. The introduction of iterative reconstruction requires such an approach to ensure that dose reduction does not impair diagnostics.
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OBJECTIVE: To review and update the conceptual framework, indicator content and research priorities of the Organisation for Economic Cooperation and Development's (OECD) Health Care Quality Indicators (HCQI) project, after a decade of collaborative work. DESIGN: A structured assessment was carried out using a modified Delphi approach, followed by a consensus meeting, to assess the suite of HCQI for international comparisons, agree on revisions to the original framework and set priorities for research and development. SETTING: International group of countries participating to OECD projects. PARTICIPANTS: Members of the OECD HCQI expert group. RESULTS: A reference matrix, based on a revised performance framework, was used to map and assess all seventy HCQI routinely calculated by the OECD expert group. A total of 21 indicators were agreed to be excluded, due to the following concerns: (i) relevance, (ii) international comparability, particularly where heterogeneous coding practices might induce bias, (iii) feasibility, when the number of countries able to report was limited and the added value did not justify sustained effort and (iv) actionability, for indicators that were unlikely to improve on the basis of targeted policy interventions. CONCLUSIONS: The revised OECD framework for HCQI represents a new milestone of a long-standing international collaboration among a group of countries committed to building common ground for performance measurement. The expert group believes that the continuation of this work is paramount to provide decision makers with a validated toolbox to directly act on quality improvement strategies.
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Construction of multiple sequence alignments is a fundamental task in Bioinformatics. Multiple sequence alignments are used as a prerequisite in many Bioinformatics methods, and subsequently the quality of such methods can be critically dependent on the quality of the alignment. However, automatic construction of a multiple sequence alignment for a set of remotely related sequences does not always provide biologically relevant alignments.Therefore, there is a need for an objective approach for evaluating the quality of automatically aligned sequences. The profile hidden Markov model is a powerful approach in comparative genomics. In the profile hidden Markov model, the symbol probabilities are estimated at each conserved alignment position. This can increase the dimension of parameter space and cause an overfitting problem. These two research problems are both related to conservation. We have developed statistical measures for quantifying the conservation of multiple sequence alignments. Two types of methods are considered, those identifying conserved residues in an alignment position, and those calculating positional conservation scores. The positional conservation score was exploited in a statistical prediction model for assessing the quality of multiple sequence alignments. The residue conservation score was used as part of the emission probability estimation method proposed for profile hidden Markov models. The results of the predicted alignment quality score highly correlated with the correct alignment quality scores, indicating that our method is reliable for assessing the quality of any multiple sequence alignment. The comparison of the emission probability estimation method with the maximum likelihood method showed that the number of estimated parameters in the model was dramatically decreased, while the same level of accuracy was maintained. To conclude, we have shown that conservation can be successfully used in the statistical model for alignment quality assessment and in the estimation of emission probabilities in the profile hidden Markov models.