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1.
MMWR Morb Mortal Wkly Rep ; 68(47): 1089-1095, 2019 Nov 29.
Article in English | MEDLINE | ID: mdl-31774743

ABSTRACT

Human immunodeficiency virus (HIV) case-based surveillance (CBS) systematically and continuously collects available demographic and health event data (sentinel events*) about persons with HIV infection from diagnosis and, if available, throughout routine clinical care until death, to characterize HIV epidemics and guide program improvement (1,2). Surveillance signals such as high viral load, mortality, or recent HIV infection can be used for rapid public health action. To date, few standardized assessments have been conducted to describe HIV CBS systems globally (3,4). For this assessment, a survey was disseminated during May-July 2019 to all U.S. President's Emergency Plan for AIDS Relief (PEPFAR)-supported countries with CDC presence† (46) to describe CBS implementation and identify facilitators and barriers. Among the 39 (85%) countries that responded,§ 20 (51%) have implemented CBS, 15 (38%) were planning implementation, and four (10%)¶ had no plans for implementation. All countries with CBS reported capturing information at the point of diagnosis, and 85% captured sentinel event data. The most common characteristic (75% of implementation countries) that facilitated implementation was using a health information system for CBS. Barriers to CBS implementation included lack of country policies/guidance on mandated reporting of HIV and on CBS, lack of unique identifiers to match and deduplicate patient-level data, and lack of data security standards. Although most surveyed countries reported implementing or planning for implementation of CBS, these barriers need to be addressed to implement effective HIV CBS that can inform the national response to the HIV epidemic.


Subject(s)
Global Health/economics , HIV Infections/epidemiology , Population Surveillance , Developing Countries , Humans , International Cooperation , United States
2.
BMJ Open ; 9(5): e027689, 2019 05 16.
Article in English | MEDLINE | ID: mdl-31101699

ABSTRACT

OBJECTIVES: Achieving the Sustainable Development Goals will require data-driven public health action. There are limited publications on national health information systems that continuously generate health data. Given the need to develop these systems, we summarised their current status in low-income and middle-income countries. SETTING: The survey team jointly developed a questionnaire covering policy, planning, legislation and organisation of case reporting, patient monitoring and civil registration and vital statistics (CRVS) systems. From January until May 2017, we administered the questionnaire to key informants in 51 Centers for Disease Control country offices. Countries were aggregated for descriptive analyses in Microsoft Excel. RESULTS: Key informants in 15 countries responded to the questionnaire. Several key informants did not answer all questions, leading to different denominators across questions. The Ministry of Health coordinated case reporting, patient monitoring and CRVS systems in 93% (14/15), 93% (13/14) and 53% (8/15) of responding countries, respectively. Domestic financing supported case reporting, patient monitoring and CRVS systems in 86% (12/14), 75% (9/12) and 92% (11/12) of responding countries, respectively. The most common uses for system-generated data were to guide programme response in 100% (15/15) of countries for case reporting, to calculate service coverage in 92% (12/13) of countries for patient monitoring and to estimate the national burden of disease in 83% (10/12) of countries for CRVS. Systems with an electronic component were being used for case reporting, patient monitoring, birth registration and death registration in 87% (13/15), 92% (11/12), 77% (10/13) and 64% (7/11) of responding countries, respectively. CONCLUSIONS: Most responding countries have a solid foundation for policy, planning, legislation and organisation of health information systems. Further evaluation is needed to assess the quality of data generated from systems. Periodic evaluations may be useful in monitoring progress in strengthening and harmonising these systems over time.


Subject(s)
Health Information Systems/organization & administration , Sustainable Development , Developing Countries , Goals , Health Information Systems/legislation & jurisprudence , Humans , Public Health
3.
JMIR Public Health Surveill ; 4(4): e10436, 2018 Dec 13.
Article in English | MEDLINE | ID: mdl-30545805

ABSTRACT

BACKGROUND: A universal health care identifier (UHID) facilitates the development of longitudinal medical records in health care settings where follow up and tracking of persons across health care sectors are needed. HIV case-based surveillance (CBS) entails longitudinal follow up of HIV cases from diagnosis, linkage to care and treatment, and is recommended for second generation HIV surveillance. In the absence of a UHID, records matching, linking, and deduplication may be done using score-based persons matching algorithms. We present a stepwise process of score-based persons matching algorithms based on demographic data to improve HIV CBS and other longitudinal data systems. OBJECTIVE: The aim of this study is to compare deterministic and score-based persons matching algorithms in records linkage and matching using demographic data in settings without a UHID. METHODS: We used HIV CBS pilot data from 124 facilities in 2 high HIV-burden counties (Siaya and Kisumu) in western Kenya. For efficient processing, data were grouped into 3 scenarios within (1) HIV testing services (HTS), (2) HTS-care, and (3) within care. In deterministic matching, we directly compared identifiers and pseudo-identifiers from medical records to determine matches. We used R stringdist package for Jaro, Jaro-Winkler score-based matching and Levenshtein, and Damerau-Levenshtein string edit distance calculation methods. For the Jaro-Winkler method, we used a penalty (р)=0.1 and applied 4 weights (ω) to Levenshtein and Damerau-Levenshtein: deletion ω=0.8, insertion ω=0.8, substitutions ω=1, and transposition ω=0.5. RESULTS: We abstracted 12,157 cases of which 4073/12,157 (33.5%) were from HTS, 1091/12,157 (9.0%) from HTS-care, and 6993/12,157 (57.5%) within care. Using the deterministic process 435/12,157 (3.6%) duplicate records were identified, yielding 96.4% (11,722/12,157) unique cases. Overall, of the score-based methods, Jaro-Winkler yielded the most duplicate records (686/12,157, 5.6%) while Jaro yielded the least duplicates (546/12,157, 4.5%), and Levenshtein and Damerau-Levenshtein yielded 4.6% (563/12,157) duplicates. Specifically, duplicate records yielded by method were: (1) Jaro 5.7% (234/4073) within HTS, 0.4% (4/1091) in HTS-care, and 4.4% (308/6993) within care, (2) Jaro-Winkler 7.4% (302/4073) within HTS, 0.5% (6/1091) in HTS-care, and 5.4% (378/6993) within care, (3) Levenshtein 6.4% (262/4073) within HTS, 0.4% (4/1091) in HTS-care, and 4.2% (297/6993) within care, and (4) Damerau-Levenshtein 6.4% (262/4073) within HTS, 0.4% (4/1091) in HTS-care, and 4.2% (297/6993) within care. CONCLUSIONS: Without deduplication, over reporting occurs across the care and treatment cascade. Jaro-Winkler score-based matching performed the best in identifying matches. A pragmatic estimate of duplicates in health care settings can provide a corrective factor for modeled estimates, for targeting and program planning. We propose that even without a UHID, standard national deduplication and persons-matching algorithm that utilizes demographic data would improve accuracy in monitoring HIV care clinical cascades.

4.
J Commun Disord ; 75: 37-56, 2018.
Article in English | MEDLINE | ID: mdl-30005318

ABSTRACT

BACKGROUND: 22q11.2 deletion syndrome (22q11.2DS) is a genetic condition associated with a highly variable phenotypic expression. During childhood speech and language deficits are commonly observed. Findings of cross-sectional studies suggest syndrome-specific and changing language profiles, but a longitudinal approach to identify developmental changes is still lacking to date. AIMS: The present study aimed to delineate language characteristics and trajectories by comparing the performance of Dutch-speaking school-aged children with 22q11.2DS (n = 18) to those of peers with idiopathic intellectual disability (IID, n  = 19) and to those of children with IID and comorbid autism spectrum disorder (IID + ASD, n = 23). The literature shows contradictory findings regarding language comprehension difficulties in children with 22q11.2DS, we focused on the receptive-expressive language discrepancy. Given their relative strength for verbal short-term memory (VSTM) tasks, a fine-grained error categorization was included to elucidate a possible influence of VSTM on the expressive language outcomes. Finally, we suggested that the inability of children with 22q11.2DS to use contextual information could interfere with morphosyntactic measures. METHODS: All groups (22q11.2DS, IID, and IID + ASD) were matched for nonverbal fluid reasoning (Gf) using the Analogies and Categories subtests of the Snijders-Oomen Nonverbal Intelligence Test or the Matrix Reasoning and Picture Concepts subtests of the Wechsler Preschool and Primary Scale of Intelligence. Several structural language skills were measured using the Clinical Evaluation of Language Fundamentals and Peabody Picture Vocabulary Test. The same instruments were re-administered after 18 to 24 months. A fine-grained error analysis of the Formulating and Recalling Sentences subtests, both measuring expressive syntax, explored factors contributing to expressive language deficits. RESULTS: In children with 22q11.2DS the relative advantage of receptive over expressive language had decreased compared to children with IID. For children with 22q11.2DS, complex sentence comprehension remained very challenging over time. Expressive language skills seemed less limited compared to children with IID, and were accompanied by less VSTM difficulties. In children with 22q11.2DS and children with IID + ASD, variable patterns of strengths and weaknesses were demonstrated, resulting in subtle differences between these groups. Error analyses indicated disregard of content-contextual cues and use of vague and elliptic language as being typical for children with 22q11.2DS. CONCLUSIONS: We recommend that in children with 22q11.2DS the impact of the receptive language impairment should be comprehensively examined and followed-up since it can have a negative effect on their social communication skills, adaptive functioning and academic achievement. Error analysis underscores that multiple measures should be used to evaluate the child's expressive language ability. Further research should focus on developmental trajectories of social communication skills and on the use of intervention strategies to improve language comprehension and pragmatics in school-aged children with 22q11.2DS.


Subject(s)
22q11 Deletion Syndrome/genetics , Child Language , Communication Disorders , Comprehension , Autism Spectrum Disorder/genetics , Child , Cross-Sectional Studies , Female , Humans , Intellectual Disability/genetics , Male , Netherlands , Wechsler Scales/statistics & numerical data
5.
Res Dev Disabil ; 81: 89-102, 2018 Oct.
Article in English | MEDLINE | ID: mdl-29936018

ABSTRACT

BACKGROUND: Development of cognitive skills and social responsiveness are areas of concern in children with 22q11.2 deletion syndrome (22q11DS). It remains unclear if the cognitive and social profiles and trajectories are syndrome-specific or similar to those of children with idiopathic intellectual disabilities (IID) with or without comorbid autism spectrum disorder (ASD). AIMS AND METHODS: In this exploratory study, we examined and compared five broad cognitive abilities (BCAs) and the social responsiveness in primary school-aged children with 22q11DS (age 6-13, n = 21) and IQ-matched peers with IID (n = 21). The relative strengths and weaknesses of both groups were re-evaluated after 19 to 30 months. OUTCOMES AND RESULTS: Four different cognitive trajectories (i.e. absolute progress, stability, growing into deficit, and absolute decline) were demonstrated in both groups. Most children showed combined types of trajectories across BCAs resulting in a complex changing cognitive profile. In the 22q11DS group, social responsiveness problems increased, whereas no significant change was observed in the IID group. CONCLUSIONS AND IMPLICATIONS: Results reflect similar cognitive and social responsiveness profiles and trajectories across groups with children with 22q11DS being more at risk for growing into a social deficit. We recommend repeated monitoring of social skills development to adapt the environmental demands to the child's individual social capacities.


Subject(s)
Cognition , DiGeorge Syndrome , Intellectual Disability , Social Skills , Child , Child Development , DiGeorge Syndrome/diagnosis , DiGeorge Syndrome/psychology , Female , Humans , Intellectual Disability/diagnosis , Intellectual Disability/psychology , Male , Monitoring, Physiologic/methods , Neuropsychological Tests , Population
6.
Int J Speech Lang Pathol ; 19(5): 490-502, 2017 10.
Article in English | MEDLINE | ID: mdl-27690637

ABSTRACT

PURPOSE: This study describes the performance on a perspective- and role-taking task in 27 children, ages 6-13 years, with 22q11.2 deletion syndrome (22q11.2DS). A cross-cultural design comparing Dutch- and English-speaking children with 22q11.2DS explored the possibility of cultural differences. METHOD: Chronologically age-matched and younger typically developing (TD) children matched for receptive vocabulary served as control groups to identify challenges in referential communication. RESULTS: The utterances of children with 22q11.2DS were characterised as short and simple in lexical and grammatical terms. However, from a language use perspective, their utterances were verbose, ambiguous and irrelevant given the pictured scenes. They tended to elaborate on visual details and conveyed off-topic, extraneous information when participating in a barrier-game procedure. Both types of aberrant utterances forced a listener to consistently infer the intended message. Moreover, children with 22q11.2DS demonstrated difficulty selecting correct speech acts in accordance with contextual cues during a role-taking task. CONCLUSION: Both English- and Dutch-speaking children with 22q11.2DS showed impoverished information transfer and an increased number of elaborations, suggesting a cross-cultural syndrome-specific feature.


Subject(s)
22q11 Deletion Syndrome/complications , Communication Disorders/etiology , Adolescent , Child , Female , Humans , Language , Male
7.
Article in English | MEDLINE | ID: mdl-28149444

ABSTRACT

Introduction: Developing countries are increasingly strengthening national health information systems (HIS) for evidence-based decision-making. However, the inability to report indicator data automatically from electronic medical record systems (EMR) hinders this process. Data are often printed and manually re-entered into aggregate reporting systems. This affects data completeness, accuracy, reporting timeliness, and burdens staff who support routine indicator reporting from patient-level data. Method: After conducting a feasibility test to exchange indicator data from Open Medical Records System (OpenMRS) to District Health Information System version 2 (DHIS2), we conducted a field test at a health facility in Kenya. We configured a field-test DHIS2 instance, similar to the Kenya Ministry of Health (MOH) DHIS2, to receive HIV care and treatment indicator data and the KenyaEMR, a customized version of OpenMRS, to generate and transmit the data from a health facility. After training facility staff how to send data using DHIS2 reporting module, we compared completeness, accuracy and timeliness of automated indicator reporting with facility monthly reports manually entered into MOH DHIS2. Results: All 45 data values in the automated reporting process were 100% complete and accurate while in manual entry process, data completeness ranged from 66.7% to 100% and accuracy ranged from 33.3% to 95.6% for seven months (July 2013-January 2014). Manual tally and entry process required at least one person to perform each of the five reporting activities, generating data from EMR and manual entry required at least one person to perform each of the three reporting activities, while automated reporting process had one activity performed by one person. Manual tally and entry observed in October 2013 took 375 minutes. Average time to generate data and manually enter into DHIS2 was over half an hour (M=32.35 mins, SD=0.29) compared to less than a minute for automated submission (M=0.19 mins, SD=0.15). Discussion and Conclusion: The results indicate that indicator data sent electronically from OpenMRS-based EMR at a health facility to DHIS2 improves data completeness, eliminates transcription errors and delays in reporting, and reduces the reporting burden on human resources. This increases availability of quality indicator data using available resources to facilitate monitoring service delivery and measuring progress towards set goals.

8.
Eur J Orthod ; 38(3): 227-34, 2016 Jun.
Article in English | MEDLINE | ID: mdl-26136435

ABSTRACT

OBJECTIVES: Insufficient attention is given in the literature to the early treatment of anterior open bite (AOB) subjects receiving orofacial myofunctional therapy (OMT), which aims to harmonize the orofacial functions. This prospective pilot study investigates the effects of OMT on tongue behaviour in children with AOB and a visceral swallowing pattern. MATERIALS AND METHODS: The study comprised of 22 children (11 boys, 11 girls; age range: 7.1-10.6 years). They were randomly assigned into OMT and non-OMT subjects. The randomization was stratified on the presence of a transversal crossbite. At baseline (T0), at the end of treatment (T1) and at 6 months after T1 (T2) maximum tongue elevation strength was measured with the IOPI system (IOPI MEDICAL LLC, Redmond, Washington, USA). Functional characteristics such as tongue posture at rest, swallowing pattern and articulation and the presence of an AOB were observed. RESULTS: OMT did significantly change tongue elevation strength, tongue posture at rest, and tongue position during swallowing of solid food. At T2 more OMT subjects had contact between the lower central incisors and their antagonists or palate (P = 0.036). More OMT subjects performed a physiological pattern of water swallowing than non-OMT children at T1 and T2, although the differences were not significant. Articulation of /s,l,n,d,t/ was not improved by OMT. No interaction between OMT and expansion was found for any of the parameters. CONCLUSION: OMT can positively influence tongue behaviour. However, further research is recommended to clarify the success of OMT as an adjunct to orthodontic treatment and to identify possible factors influencing the outcome.


Subject(s)
Myofunctional Therapy/methods , Open Bite/therapy , Tongue/physiopathology , Child , Deglutition/physiology , Deglutition Disorders/physiopathology , Female , Humans , Incisor/physiopathology , Male , Malocclusion/physiopathology , Open Bite/physiopathology , Palate/physiopathology , Pilot Projects , Prospective Studies
9.
Logoped Phoniatr Vocol ; 36(4): 139-44, 2011 Dec.
Article in English | MEDLINE | ID: mdl-21385021

ABSTRACT

In this study we investigated how important significant others find it to be informed, supported, and trained by speech-language pathologists (SLPs) and to what extent they perceive their expectations and needs as to these aspects to be fulfilled. Furthermore SLPs were asked about the importance of informing and supporting family members and as to how far they believe they provide adequate care in that field. A questionnaire was completed by 77 relatives of persons with aphasia, a parallel version by 132 SLPs. More than 50% of all aspects concerning information and support were considered as (very) important by family members and SLPs alike. Nevertheless family members felt that some of their needs indicated as important were insufficiently met by SLPs.


Subject(s)
Aphasia/rehabilitation , Caregivers/psychology , Family Relations , Health Knowledge, Attitudes, Practice , Health Services Needs and Demand , Patient Education as Topic , Social Support , Speech-Language Pathology , Spouses/psychology , Access to Information , Adult , Aphasia/psychology , Attitude of Health Personnel , Belgium , Chi-Square Distribution , Child , Cost of Illness , Female , Humans , Male , Middle Aged , Parent-Child Relations , Perception , Personal Satisfaction , Surveys and Questionnaires
10.
Stud Health Technol Inform ; 160(Pt 1): 411-5, 2010.
Article in English | MEDLINE | ID: mdl-20841719

ABSTRACT

We have adopted the Open Medical Record System (OpenMRS) framework to implement an electronic patient monitoring system for an HIV care and treatment program in Mozambique. The program provides technical assistance to the Ministry of Health supporting the scale up of integrated HIV care and support services in health facilities in rural resource limited settings. The implementation is in use for adult and pediatric programs, with ongoing roll-out to cover all supported sites. We describe early experiences in adapting the system to the program needs, addressing infrastructure challenges, creating a regional support team, training data entry staff, migrating a legacy database, deployment, and current use. We find that OpenMRS offers excellent prospects for in-country development of health information systems, even in severely resource limited settings. However, it also requires considerable organizational infrastructure investment and technical capacity building to ensure continued local support.


Subject(s)
Database Management Systems/organization & administration , Delivery of Health Care/organization & administration , Electronic Health Records/organization & administration , HIV Infections/diagnosis , HIV Infections/therapy , Medical Record Linkage/methods , Rural Health Services/organization & administration , HIV Infections/epidemiology , Information Storage and Retrieval/methods , Mozambique , Population Surveillance/methods
11.
Retrovirology (Auckl) ; 3: 1-14, 2010 Apr 23.
Article in English | MEDLINE | ID: mdl-25097450

ABSTRACT

Mozambique has severe resource constraints, yet with international partnerships, the nation has placed over 145,000 HIV-infected persons on antiretroviral therapies (ART) through May-2009. HIV clinical services are provided at > 215 clinical venues in all 11 of Mozambique's provinces. Friends in Global Health (FGH), affiliated with Vanderbilt University in the United States (US), is a locally licensed non-governmental organization (NGO) working exclusively in small city and rural venues in Zambézia Province whose population reaches approximately 4 million persons. Our approach to clinical capacity building is based on: 1) technical assistance to national health system facilities to implement ART clinical services at the district level, 2) human capacity development, and 3) health system strengthening. Challenges in this setting are daunting, including: 1) human resource constraints, 2) infrastructure limitations, 3) centralized care for large populations spread out over large distances, 4) continued high social stigma related to HIV, 5) limited livelihood options in rural areas and 6) limited educational opportunities in rural areas. Sustainability in rural Mozambique will depend on transitioning services from emergency foreign partners to local authorities and continued funding. It will also require "wrap-around" programs that help build economic capacity with agricultural, educational, and commercial initiatives. Sustainability is undermined by serious health manpower and infrastructure limitations. Recent U.S. government pronouncements suggest that the U.S. President's Emergency Plan for AIDS Relief will support concurrent community and business development. FGH, with its Mozambican government counterparts, see the evolution of an emergency response to a sustainable chronic disease management program as an essential and logical step. We have presented six key challenges that are essential to address in rural Mozambique.

12.
Clin Oral Implants Res ; 19(1): 86-90, 2008 Jan.
Article in English | MEDLINE | ID: mdl-17944967

ABSTRACT

OBJECTIVES: The objective of the present study was to evaluate the influence of immediate loading of implants on speech adaptation. MATERIAL AND METHODS: Ten patients (mean age 54, 6 females) were examined before surgery and 1, 3, 6 and 12 months afterwards. Articulation analysis was done using objective DAT-recoded data evaluated by two groups of speech and language therapists and a computer software program. Besides, patient VAS-scores, myofunctional problems and hearing impairment were recorded and analysed. RESULTS: In the present study only one patient suffered from deteriorated speech after immediate loading. Other patients showed unaffected or improved articulation 3 to 6 months after surgery with a strident and interdental pronunciation mostly becoming addental. Furthermore, myofunctional problems occurred in one patient, other patients adapted to the new situation after three months. Hearing impairment did not influence speech pathology in this study. CONCLUSION: Immediate loading of oral implants does not seem to compromise the normal 3-6 months speech adaptation period. Whether such procedure presents advantages to the conventional 2-stage rehabilitation remains to be investigated.


Subject(s)
Adaptation, Physiological , Dental Prosthesis, Implant-Supported , Mouth, Edentulous/rehabilitation , Speech/physiology , Adult , Aged , Analysis of Variance , Articulation Disorders/etiology , Dental Implantation, Endosseous , Dental Prosthesis, Implant-Supported/adverse effects , Dental Stress Analysis , Denture, Complete, Immediate , Facial Muscles/physiology , Female , Hearing Tests , Humans , Male , Middle Aged , Patient Satisfaction , Speech Articulation Tests , Statistics, Nonparametric , Tape Recording , Time Factors
13.
Habitation (Elmsford) ; 10(2): 105-15, 2005.
Article in English | MEDLINE | ID: mdl-15742536

ABSTRACT

This article presents the design and implementation of a controller scheme for efficient resource management in Advanced Life Support Systems. In the proposed approach, a switching hybrid system model is used to represent the dynamics of the system components and their interactions. The operational specifications for the controller are represented by utility functions, and the corresponding resource management problem is formulated as a safety control problem. The controller is designed as a limited-horizon online supervisory controller that performs a limited forward search on the state-space of the system at each time step, and uses the utility functions to decide on the best action. The feasibility and accuracy of the online algorithm can be assessed at design time. We demonstrate the effectiveness of the scheme by running a set of experiments on the Reverse Osmosis (RO) subsystem of the Water Recovery System (WRS).


Subject(s)
Ecological Systems, Closed , Equipment Safety/instrumentation , Life Support Systems/instrumentation , Neural Networks, Computer , Space Flight/instrumentation , Water Purification/instrumentation , Algorithms , Artificial Intelligence , Computer Simulation , Decision Support Techniques , Models, Theoretical , Osmosis , Systems Theory
14.
Logoped Phoniatr Vocol ; 29(1): 13-7, 2004.
Article in English | MEDLINE | ID: mdl-15089000

ABSTRACT

Gathering information from parents on developmental history and on actual functioning is an important element of diagnosis. Usually clinicians take it for granted that the data provided this way are reliable. We used two types of questionnaires, one containing open-ended questions, the other consisting of closed questions. By comparing the answers to both types filled in by fathers (2 x 50) and mothers (2 x 50) independently we tried to verify the interreliability of the data collected. We found a general degree of unanimity of 82%, dropping to only 48% on questions regarding early milestones of speech and language development. We found differences between the two types of questionnaires: more questions were left unanswered in the open-question type questionnaire, more differing answers were observed in a closed-question type questionnaire. Some factors might have had an influence on reliability, such as socio-economic background of the parents, differences between data on first and only children versus children from larger families. Although data collecting, including history taking, is, and will stay an important source for information gathering, clinicians have to be careful in interpreting them.


Subject(s)
Data Collection/standards , Language Development , Child, Preschool , Family Characteristics , Female , Humans , Language Disorders/diagnosis , Male , Regression Analysis , Reproducibility of Results , Socioeconomic Factors , Surveys and Questionnaires/standards
15.
Habitation (Elmsford) ; 10(1): 21-37, 2004.
Article in English | MEDLINE | ID: mdl-15880907

ABSTRACT

This article describes methods for online model-based diagnosis of subsystems of the advanced life support system (ALS). The diagnosis methodology is tailored to detect, isolate, and identify faults in components of the system quickly so that fault-adaptive control techniques can be applied to maintain system operation without interruption. We describe the components of our hybrid modeling scheme and the diagnosis methodology, and then demonstrate the effectiveness of this methodology by building a detailed model of the reverse osmosis (RO) system of the water recovery system (WRS) of the ALS. This model is validated with real data collected from an experimental testbed at NASA JSC. A number of diagnosis experiments run on simulated faulty data are presented and the results are discussed.


Subject(s)
Ecological Systems, Closed , Equipment Safety/instrumentation , Life Support Systems/instrumentation , Neural Networks, Computer , Water Purification/instrumentation , Algorithms , Artificial Intelligence , Computer Simulation , Decision Support Techniques , Models, Theoretical , Osmosis , Space Flight , Systems Theory
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