Search results for "Protocol"
showing 10 items of 1808 documents
Performance Study of Non-beaconed and Beacon-Enabled Modes in IEEE 802.15.4 under Bluetooth Interference
2008
The IEEE 802.15.4 protocol is a flexible technology with great potential for wireless sensor networks applications. The standard distinguishes two network modes; beacon-enabled and nonbeacon-enabled. In this paper, the performance study of beaconed and non-beaconed modes of IEEE 802.15.4 is evaluated using on site PER measurements. The tests are carryout in an urban outdoor environment with commercial available equipment. Likewise, the impact of Bluetooth interference over IEEE 802.15.4 modes is evaluated. The results show that Bluetooth interference and the mode selected have effects over the PER. Furthermore, for distances between 3 to 10 meters the PER doesn't show significance distance …
An Experimental Testbed and Methodology for Characterizing IEEE 802.11 Network Cards
2006
It has been observed that IEEE 802.11 commercial cards produced by different vendors show a different behavior in terms of perceived throughput or access delay. Performance differences are evident both when the cards contend alone to the channel, and when heterogeneous cards contend together. Since the performance misalignment does not disappear by averaging the environmental factors (such as propagation conditions, laptop models, traffic generators, etc), it is evident that the well known throughput-fairness property of the DCF protocol is not guaranteed in actual networks. In this paper we propose a methodological approach devised to experimentally characterize the IEEE 802.11 commercial …
A phase-II study of low-dose cyclophosphamide and recombinant human interleukin-2 in metastatic renal cell carcinoma and malignant melanoma.
1989
Recent preclinical and clinical studies that have demonstrated antitumor activity of high-dose recombinant interleukin-2 (rIL-2), and animal models that demonstrated a synergistic effect of low-dose cyclophosphamide, led us to study rIL-2 (Cetus Corp., Emeryville, Calif) in a phase II clinical trial in combination with low-dose cyclophosphamide in 32 patients, 18 with malignant melanoma and 14 with renal cell carcinoma. rIL-2 was given once daily at 3 x 10(6) U/m2, as a 30-min infusion for 14 days in cycle I and for 2 x 5 days in cycles II and III respectively; if tolerated, the dose was increased to a maximum of 6 x 10(6) U m-2 day-1; the cycles, separated by 1 week treatment-free interval…
The EU’s Role in International Climate Change Policy-Making: A Global Leader in Decline?
2013
This chapter assesses the European Union’s (EU) role in international climate change policy-making by comparing the EU’s degree of goal attainment at the United Nations Framework Convention on Climate Change (UNFCCC) Conference of the Parties (COP) negotiations in Copenhagen in 2009 and Cancun in 2010. By making use of three analytical factors (coherence, the opportunity structure and politicisation) we assess the outcomes of both negotiations for the EU. The Durban negotiations of 2011 are touched upon in the conclusions.
EECDC-MAC: An energy efficient cooperative duty cycle MAC protocol
2012
In this paper, we propose a novel energy efficient cooperative duty cycle MAC (EECDC-MAC) protocol in which sensor nodes use fixed wakeup rendezvous scheduling to exchange messages and a cooperative transmission mechanism to avoid overuse of nodes with lower residual energy. Numerical results demonstrate that the EECDC-MAC protocol can prolong the entire network longevity efficiently in comparison with an existing cooperative duty cycle MAC protocol, CDC-MAC, and another popular duty cycle MAC protocol, prediction wakeup MAC (PW-MAC) protocol.
Formal verification of a Cooperative Automatic Repeat reQuest MAC protocol
2012
Author's version of an article published in the journal: Computer Standards & Interfaces. Also available from the publisher at: http://dx.doi.org/10.1016/j.csi.2011.12.001 Cooperative communications, in which a relay node helps the source node to deliver its packets to the destination node, are able to obtain significant benefits in terms of transmission reliability, coverage extension and energy efficiency. A Cooperative Automatic Repeat reQuest (C-ARQ) MAC protocol has been recently proposed to exploit cooperative diversity at the MAC layer. in this paper, we validate the integrity and the validity of the C-ARQ protocol using formal methods. The protocol logic is modeled in SDL and implem…
Updating the OSPF routing protocol for communication networks by optimal decision-making over the k-shortest path algorithm
2019
Internet routing protocols such as Routing Information Protocol (RIP) pre-compute all the shortest paths by Dijkstra's algorithm (shortest path first, SPF) based on the number of hops between one node and another. Every time any communication is intended, RIP looks-up for the optimal choice in a routing table. This is a high speed method in the decision-making process but not necessary fast for data traffic as it does not take into account any real-time measure of route congestion. Open Shortest Path First (OSPF) presents a dynamic version of this problem by computing the shortest paths taking into account network features such as bandwidth, delay and load. OSPF thereby maintains link-state…
Internet-based perioperative exercise program in patients with Barrett’s carcinoma scheduled for esophagectomy [iPEP - study] a prospective randomize…
2017
Abstract Background Patients undergoing surgery for esophageal cancer have a high risk for postoperative deterioration of lung function and pulmonary complications. This is partly due to one-lung ventilation during thoracotomy. This often accounts for prolonged stay on intensive care units, delayed postoperative reconvalescence and reduced quality of life. Socioeconomic disadvantages can result from these problems. Physical preconditioning has become a crucial leverage to optimize fitness and lung function in patients scheduled for esophagectomy, in particular during the time period of neoadjuvant therapy. Methods/Study design We designed a prospective multicenter randomized-controlled tria…
En el interior de los hospitales. Personas, espacios y enseres
2010
Las instituciones hospitalarias medievales son objeto de numerosos estudios desde diversas perspectivas y modelos de investigación: tipología, orígenes, régimen económico y administrativo, aspectos histórico-médicos, etc., pero no es fácil estudiar cuestiones que atañen a su estructura arquitectónica, al reparto de espacios, a su organización, mobiliario o enseres, entre otros muchos aspectos. Los inventarios que en ocasiones se hacían de estos centros, son una fuente importante para poder conocer estos aspectos. En este trabajo estudiamos los que se realizaron, a finales del siglo XV, en los hospitales más importantes de la ciudad de Valencia. (A)
Cooperative Inventory control
2005
In multi-retailer inventory control the possibility of sharing setup costs motivates communication and coordination among the retailers. We solve the problem of finding suboptimal distributed reordering policies that minimize setup, ordering, storage, and shortage costs incurred by the retailers over a finite horizon. Neuro-dynamic programming (NDP) reduces the computational complexity of the solution algorithm from exponential to polynomial on the number of retailers.