Maritime Piracy: Solving the Optimized Transit Path Problem

Models have been developed that accurately predict the probability of pirate activity at locations throughout the Arabian Sea. With these piracy prediction models, mariners transiting this region can ensure that their course avoids the highest threat regions and that ample anti-piracy precautions are in place elsewhere. However, they are on their own to determine their "best" transit path. Using unique piracy success predictors and transit cost calculators, along with existing pirate activity predictions, this research develops a method for determining the Optimized Transit Path through the Arabian Sea. This method simultaneously optimizes two different attributes, piracy avoidance and cost minimization, based on a mariner's priorities. The Optimized Transit Path (OTP) algorithm calculates the minimum cumulative path through a two-dimensional, geographic matrix. The OTP algorithm finds the shortest path through the network from a starting line on one side of the matrix to a finish line on the other side. Using a computer code of the algorithm, experimental tests quantified the OTP algorithm's computation speed and required number of calculations to reach a solution. Further, the performance of the OTP algorithm at solving the piracy matrix was compared to the speed of other shortest path algorithms. Based on this study, the OTP algorithm's speed at solving the piracy matrix was comparable to that of the fastest shortest path algorithm in use today, Dijkstra's Algorithm implementing a Min-Priority queue with a Fibonacci Heap, and significantly faster than all others. Because it can use the piracy prediction matrix directly as an input, the OTP algorithm is especially well suited for solving the piracy avoidance problem. More importantly, its calculation of Optimized Slack quantifies the additional cost of diverting from the shortest path, information not calculated by other shortest path methods. However, use of the OTP algorithm is fairly limited, as it is only well suited for matrices that represent a flat plane of interconnected geographic areas, with movement from a node limited to the eight adjacent nodes surrounding it. Another promising application of the methods in this paper is within the field of underwater search

VII Jornadas de Expania

Sección: Noticias. Noticias externasLos días 27 y 28 de mayo se celebraron en Santiago de Compostela las VII Jornadas de Expania, la Asociación de Usuarios de Ex Libris en España.N

Intravenous immunoglobulin in the treatment of primary trigeminal neuralgia refractory to carbamazepine: a study protocol[ISRCTN33042138]

BACKGROUND: We have recently reported successful treatment of patients with chronic pain syndromes using human pooled intravenous immunoglobulin (IVIG) in a prospective, open-label cohort study. A randomised, placebo controlled, double blinded study is needed to confirm these results. We chose to study patients with carbamazepine resistant primary Trigeminal Neuralgia (rpTN), as these had responded particularly well to IVIG. A protocol involving the use of IVIG in rpTN is complex for three reasons: 1. The effect of IVIG does not follow simple dose-response rules; 2. The response pattern of patients to IVIG was variable and ranged between no effect at all and pain free remission between two weeks and >1 year; 3. TN is characterized by extremely severe pain, for which operative intervention is (if temporarily) helpful in most patients. DESIGN: A placebo controlled, parallel, add-on model was developed and the primary outcome variable defined as the length of time during which patients remain in the study. Study groups are compared using Kaplan-Maier survival analysis. Patients record their response to treatment ("severe, moderate, slight, no pain"). The study coordinator monitors pain diaries. Severe or moderate pain of three days duration will result in termination of the study for that patient. CONCLUSIONS: This study design utilizes a method of survival analysis and is novel in chronic pain research. It allows for both early departure from the study and voluntary crossover upon non-response. It may be applicable to the analysis of IVIG efficacy in other chronic pain syndromes

Performance of the GFR-service with constant available bandwidth

minimum service guarantee to classical best-effort services. The eligibility of frames for this service category is determined with the Frame Based Generic Cell Rate Algorithm and the transmission is guaranteed by a queuing-discipline based on two thresholds. In this paper we present a discrete-time analysis of the GFR-service under the assumption of constant available bandwidth. The presented method can be applied to dimension the thresholds of the queuing discipline used to enforce the guaranteed service.