A reactive approach to obstacle avoidance in autonomous sailing.

This paper presents a reactive approach to obstacle avoidance for autonomous sailboats. It is an extension to the short course routing method published by Stelzer and Pr¨oll in 2008 which enables it to deal with obstacles in real-time. First simulation results are promising. The algorithm enables an autonomous sailboat to circumnavigate differently sized obstacles under various wind conditions successfully

Unique Keys Enabling Multithreshold Schemes

. We present a generalization of Shamir's threshold scheme [5]. The Shamir's scheme shows how to divide a key D into n pieces such that it is easily reconstructable from any k pieces, but that even complete knowledge of k \Gamma 1 pieces reveals no information about D. Shamir calls it a (k,n) threshold scheme. We propose a system with s security levels, each of them requiring k l partial keys for computation of a secret key D l for level l. The higher is the security level, the more keys are required. We call our scheme a (k l ; s; n) multithreshold scheme, l = 1; \Delta \Delta \Delta ; s. 1 Introduction We consider the following scenario. A group of ten experts is responsible for operating a protected system. To perform some minor changes in the system, at least three of them must be present. If they want to change more sensitive parts, more experts from the group have to agree. The more of them are involved, the more sensitive parts of the system under protection are accessible. W..

Fast Algorithms for the Maximum Convolution Problem

We describe two algorithms for solving the maximum convolution problem, i.e. the calculation of c k := maxfa k\Gammai + b i j 0 i n \Gamma 1g for all k with respect to given sequences (a 0 ; : : : ; an\Gamma1 ), (b 0 ; : : : ; b n\Gamma1 ) of real numbers. Our first algorithm with expected running time O(n log n) is mainly of theoretical interest while our second algorithm allows a simpler, more practicable implementation and showed quite fast performance in numerical experiments. maximum convolution; probabilistic analysis 1 Introduction For a = (a 0 ; a 1 ; : : : ; an\Gamma1 ) and b = (b 0 ; b 1 ; : : : ; b n\Gamma1 ) two sequences of real numbers, we consider the problem of computing the numbers c k , 0 k n \Gamma 1 defined by c k = max 0in\Gamma1 (a k\Gammai + b i ) (1) (all indices in this exposition are taken modulo n). We call this problem the Maximum Convolution problem, MaxCon for short. A direct calculation of sequence c from equation 1 obviously needs O(n 2 ) time..

Sex-Specific Association of Serum Anti-Oxidative Capacity and Leukocyte Telomere Length

Telomeres are a crucial factor in the preservation of genomic integrity, and an elevated risk for diseases such as cancer and cardiovascular events is related to shortened telomeres. However, telomere deterioration could be caused by factors such as chronic oxidative stress and inflammation, which are promoted by an imbalance among reactive oxygen species (ROS) and antioxidants. In this cross-sectional study, we investigated the relationship between telomeres and oxidative stress. The serum leucocyte telomer length (LTL), serum total antioxidant capacity (TAC) and the total serum lipid panel of 180 healthy athletic volunteers (90 males, 90 females) were measured Additionally, a questionnaire about sports behaviour and the type of training was completed. We observed a positive significant relation between serum LTL and TAC in the male group (cc = 3.4/p = 0.001) but not in females. There was no statistically significant correlation between age and physical activity and LTL in both groups. This is the first cross sectional study demonstrating an association between total serum TAC and LTL in healthy males, but interestingly, not in the females. Nevertheless, these results should be interpreted as preliminary, and further studies in independent cohorts are needed to investigate the sex-specific effects of oxidative stress on telomere length and telomerase activity

Investigation of the Relationship between the Mid_Thigh Adipose Tissue Distribution Measured by MRI and Serum Osteocalcin—A Sex-Based Approach

Osteocalcin, in its non-carboxylated form, has a positive effect on glucose metabolism. Additionally, osteocalcin levels are related to body composition, especially muscle mass. The relation to the distribution of different adipose tissue types, such as subcutaneous, intermuscular, and visceral adipose tissue, is unclear. This study aimed to investigate associations between serum osteocalcin and the distribution of subcutaneous and intermuscular adipose tissue of the mid-thigh. Furthermore, the influence of different training methods on osteocalcin levels was investigated. We performed adipose tissue quantification of subcutaneous adipose tissue (SAT) and intramuscular adipose tissue (IMAT) using MRI measurements of the mid-thigh in 128 volunteers (63 male/65 female). Laboratory analysis included blood lipid panel, serum insulin, adiponectin, and osteocalcin measurements. The main observation was a significant correlation of total serum osteocalcin (TOC) and the distribution of adipose tissue of the mid-thigh (SAT/(SAT + IMAT)) (cc = −0.29/p-value = 0.002), as well as the cross-sectional muscle area (MA), increasing with the weekly resistance training duration in males. Additionally, TOC (p-value = 0.01) and MA (p-value = 0.03) were negatively related to serum insulin. The significant relationship between TOC and SAT/(SAT + IMAT) is a new finding and confirms the negative influence of IMAT on glucose metabolism in a sex-specific approach. We could substantiate this by the negative relation of TOC with serum insulin