Network layer solutions for a content-centric internet

Nowadays most people exploit the Internet to get contents such as web pages, music or video files. These users only value “what” they download and are not interested about “where” content is actually stored. The IP layer does the opposite and cares about the “where” and not about the “what”. This contrast between the actual usage of the Internet and the service offered by the IP layer is deemed to be the source of several problems concerning usability, performance, security and mobility issues. To overcome this contrast, research on the Future Internet is exploring novel so-called content-centric architectures, where the network layer directly provides users with contents, instead of providing communication channels between hosts. In this paper, we identify the main functionalities of a content-centric network (CONET), we discuss pros and cons of literature proposals for an innovative, content-centric network layer and we draw our conclusions, stating some general requirements that, in our opinion, a CONET should satisfy

Fairness-oriented overlay VPN topology construction

An important issue in dynamically constructed Virtual Private Networks (VPN) is how the overlay topology is created and maintained. Classical VPN topologies, such as hub-and-spoke or full-mesh, fail to remain convenient and viable when the number of nodes grows to as little as a few tens. Convenient topology formation mechanisms should be distributed, should permit incremental and dynamic operations, and should limit the number of nodes a new entry connects with. In this work, we show that approaches devised to create “short” networks, while yielding a significant total network throughput, may be severely affected by unfairness issues, i.e., different pair of nodes may experience a widely different throughput performance. Hence, we introduce a fairness-oriented topology formation algorithm for VPN. The proposed algorithm is incremental, meaning that the addition of a new node to the overlay topology does not imply rewiring of already established overlay links. Simulation results show that our proposed approach achieves high fairness levels, as quantified in terms of well known Jain's fairness index, meanwhile retaining satisfactory throughput performance

Robust job-sequencing with an uncertain flexible maintenance activity

In this study, the problem of scheduling a set of jobs and one uncertain maintenance activity on a single machine, with the objective of minimizing the makespan is addressed. The maintenance activity has a given duration and must be executed within a given time window. Furthermore, duration and time window of the maintenance are uncertain, and can take different values which can be described by different scenarios. The problem is to determine a job sequence which performs well, in terms of makespan, independently on the possible variation of the data concerning the maintenance. A robust scheduling approach is used for the problem, in which four different measures of robustness are considered, namely, maximum absolute regret, maximum relative regret, worst-case scenario, and ordered weighted averaging. Complexity and approximation results are presented. In particular, we show that, for all the four robustness criteria, the problem is strongly NP-hard. A number of special cases are explored, and an exact pseudopolynomial algorithm based on dynamic programming is devised when the number of scenarios is fixed. Two Mixed Integer Programming (MIP) models are also presented for the general problem. Several computational experiments have been conducted to evaluate the efficiency and effectiveness of the MIP models and of the dynamic programming approach

Streaming H.264 scalable video over data distribution service in a wireless environment

The Data Distribution Service (DDS) middleware is enjoying a rapid adoption in high-performance, mission-critical networks. At the same time, the H.264 Scalable Video Coding (SVC) has been recently standardized and it is deemed to be an effective solution for video streaming over a channel with time-varying bandwidth, like the wireless one. In these conditions, it is critical to adapt the video bit-rate to the actual wireless capacity, and bit-rate adaptation is extremely simple for a H.264 SVC video. In this paper we devise, evaluate and demonstrate a technique for streaming H.264 SVC video over a DDS middleware. The contribution is threefold: i) we design a structure of the DDS data-unit able to carry H.264 SVC video-units; ii) we devise a receiver-driven rate-control mechanism based on our DDS data-unit and exploiting specific DDS functionality; iii) we implement and show the effectiveness of our mechanism in an 802.11 wireless scenario, comparing our proposal with other solution

Late Relapse and Follow-up Protocols in Testicular Germ Cell Tumours: The Edinburgh Cancer Centre Experience and Review of the Literature

Aims To identify clinicopathological features and outcomes in patients with late relapse (LR) of testicular germ cell tumours (GCTs) in order to guide follow-up policy. Materials and Methods The Edinburgh Cancer Centre (ECC) database identified all patients diagnosed with testicular GCT between 1988 and 2002. Of 703 patients, six relapsed more than 24 months after their initial treatment. A retrospective casenote review was performed to extract clinical, pathological, treatment and outcome data. Results Six patients (0.85%) underwent late relapse. All patients presented initially with stage I disease and five were classified as good risk (International Germ Cell Consensus Classification, IGCCC). Median time to LR was 31 months. Two patients had previously relapsed less than 24 months from initial diagnosis. Markers at the time of relapse were normal in all patients. In all cases of late relapse disease was confined to axial lymphadenopathy. Three patients were treated with chemotherapy alone, two patients underwent surgical resection and one patient received combined treatment. All patients obtained a complete response and all remain disease free with a median follow-up of 52 months. Conclusions The incidence of late relapse in this series is low. Chemo-naive patients with LR were successfully salvaged with chemotherapy alone and patients previously exposed to cisplatin-based chemotherapy were salvaged with complete surgical excision. The optimal length of follow-up in patients with testicular germ cell tumours is not known and practice varies widely. In this cohort of 703 patients, only one patient who relapsed was picked up by additional clinic follow-up between 5 and 10 years. Thus, on the basis of this small series, the authors suggest that follow-up after five years may not be justified

KANDUNGAN KIMIA DAN DIMENSI SERAT AKAR, CABANG DAN BATANG BAGIAN ATAS KAYU GMELINA DAN KAYU JATI DI HUTAN RAKYAT SULAWESI SELATAN

The wood species used in this research was gmelina wood from community forest, Maros Regency and jati wood from community forest, Barru Regency. For objective of the research, parts of the tree were taken a short cut (5 cm) from root, branch and top of the tree. All samples were tested their chemical component (cellulose, hemicellulose, lignin and extractives) and fiber dimensions with it’s derivates fiber. The results showed that root, branch and top of the tree of gmelina wood and jati wood from community forest can be used as a raw material for pulp and papers. Key words: Chemical content, Fiber Dimension, Gmelina Wood, Jati Wood, Community Fores