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Mobile ad hoc networks (MANETs) become more and more popular and significant in many fields. However, the important applications of MANETs make them very attractive to attackers. The deployment scenarios, the functionality requirements, and the limited capabilities of these types of networks make them vulnerable to a large group of attacks, e.g., blackhole attacks. In this paper, we propose a cluster-based scheme for the purpose of preventing blackhole attacks in MANETs. In our scheme, we firstly present a novel algorithm that employs a powerful analytic hierarchy process (AHP) methodology to elect clusterheads (CHs). Then CHs are required to implement the blackhole attacks prevention scheme to not only detect the existence of blackhole attacks but also identify the blackhole nodes. Simulation results show that our scheme is feasible and efficient in preventing blackhole attacks.

The aim of this study was to compare the safety and efficacy of OsteoSet®2 DBM with autologous cancellous bone in free vascularised fibular grafting for the treatment of large osteonecrotic lesions of the femoral head. Twenty-four patients (30 hips) with large osteonecrotic lesions of the femoral head (stage IIC in six hips, stage IIIC in 14, and stage IVC in ten, according to the classification system of Steinberg et al.) underwent free vascularised fibular grafting with OsteoSet®2 DBM. This group was retrospectively matched to a group of 24 patients (30 hips) who underwent free vascularised fibular grafting with autologous cancellous bone during the same time period according to the aetiology, stage, and size of the lesion and the mean preoperative Harris hip score. A prospective case-controlled study was then performed with a mean follow-up duration of 26 months. The results show no statistically significant differences between the two groups in overall clinical outcome or the radiographic assessment. Furthermore, no adverse events related to the use of the OsteoSet®2 DBM were observed. The results demonstrate that OsteoSet®2 DBM combined with autograft bone performs equally as well as that of autologous bone alone. Therefore, OsteoSet®2 DBM can be used as a safe and effective graft extender in free vascularised fibular grafting for large osteonecrotic lesions of the femoral head.

Reconstruction of large skeletal defects secondary to osteomyelitis or open fracture is a challenging problem. The purpose of this study was to evaluate the results of using free vascularized fibular graft (FVFG) combined with locking plate in the treatment of large skeletal defects from open fracture and infection. Ten patients with a mean age of 34 years (ranged 13–57 years) and a mean length of 8.7 cm (range 6–17 cm) skeletal defect were treated with FVFG and locking plate. The mean follow-up time was 26 months. Grafting union occurred in all patients, with a mean healing time of 4.5 months. No recurrence of osteomyelitis and stress fractures was observed. The mean time to full weight-bearing was 10 months, and all patients were pain-free and able to walk without supportive devices. FVFG combined with locking plate is a viable option for the management of large skeletal defects from open fracture and infection.