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Neste trabalho é considerada uma rede sem fio ad hoc realizada em uma grade regular quadrada, na qual a comunicação entre os dispositivos é influenciada por obstáculos regularmente espaçados. O raio crítico de transmissão para obter conectividade nesse tipo de rede cresce com o tamanho da grade, o que pode prejudicar a viabilidade em larga escala de tecnologias sem fio de baixa potência. Avalia-se portanto como introduzir eficientemente uma infraestrutura conectada de pontos de acesso em cenários subcríticos, nos quais o raio de transmissão é insuficiente para estabelecer a conectividade. Formula-se o problema de posicionar o menor número de pontos de acesso, de tal modo que todo componente conectado seja coberto por pelo menos uma estação base, e denomina-se esse problema de Obstructed Wireless Network Backbone Cover Problem (OWN-BC). Prova-se que OWN-BC é NP-Completo e propõe-se um algoritmo 2-aproximativo para obter soluções com garantia de qualidade. Realiza-se simulações para ilustrar o desempenho do algoritmo em diferentes cenários. Além disso, é feita uma caracterização de cenários para os quais o algoritmo proposto obtêm soluções ótimas em tempo polinomial com alta probabilidade.

Clinical measurement.To translate and culturally adapt the Lower Extremity Functional Scale (LEFS) into a Brazilian Portuguese version, and to test the construct and content validity and reliability of this version in patients with knee injuries.There is no Brazilian Portuguese version of an instrument to assess the function of the lower extremity after orthopaedic injury.The translation of the original English version of the LEFS into a Brazilian Portuguese version was accomplished using standard guidelines and tested in 31 patients with knee injuries. Subsequently, 87 patients with a variety of knee disorders completed the Brazilian Portuguese LEFS, the Medical Outcomes Study 36-Item Short-Form Health Survey, the Western Ontario and McMaster Universities Osteoarthritis Index, and the International Knee Documentation Committee Subjective Knee Evaluation Form and a visual analog scale for pain. All patients were retested within 2 days to determine reliability of these measures. Validation was assessed by determining the level of association between the Brazilian Portuguese LEFS and the other outcome measures. Reliability was documented by calculating internal consistency, test-retest reliability, and standard error of measurement.The Brazilian Portuguese LEFS had a high level of association with the physical component of the Medical Outcomes Study 36-Item Short-Form Health Survey (r = 0.82), the Western Ontario and McMaster Universities Osteoarthritis Index (r = 0.87), the International Knee Documentation Committee Subjective Knee Evaluation Form (r = 0.82), and the pain visual analog scale (r = -0.60) (all, P.05). The Brazilian Portuguese LEFS had a low level of association with the mental component of the Medical Outcomes Study 36-Item Short-Form Health Survey (r = 0.38, P.05). The internal consistency (Cronbach α = .952) and test-retest reliability (intraclass correlation coefficient = 0.957) of the Brazilian Portuguese version of the LEFS were high. The standard error of measurement was low (3.6) and the agreement was considered high, demonstrated by the small differences between test and retest and the narrow limit of agreement, as observed in Bland-Altman and survival-agreement plots.The translation of the LEFS into a Brazilian Portuguese version was successful in preserving the semantic and measurement properties of the original version and was shown to be valid and reliable in a Brazilian population with knee injuries.