Linear-Time Algorithms for Hole-free Rectilinear Proportional Contact Graph Representations

In a proportional contact representation of a planar graph, each vertex is represented by a simple polygon with area proportional to a given weight, and edges are represented by adjacencies between the corresponding pairs of polygons. In this paper we first study proportional contact representations that use rectilinear polygons without wasted areas (white space). In this setting, the best known algorithm for proportional contact representation of a maximal planar graph uses 12-sided rectilinear polygons and takes O(nlogn) time. We describe a new algorithm that guarantees 10-sided rectilinear polygons and runs in O(n) time. We also describe a linear-time algorithm for proportional contact representation of planar 3-trees with 8-sided rectilinear polygons and show that this is optimal, as there exist planar 3-trees that require 8-sided polygons. We then show that a maximal outer-planar graph admits a proportional contact representation using rectilinear polygons with 6 sides when the outer-boundary is a rectangle and with 4 sides otherwise. Finally we study maximal series-parallel graphs. Here we show that O(1)-sided rectilinear polygons are not possible unless we allow holes, but 6-sided polygons can be achieved with arbitrarily small holes.     

Spectral and radiometric requirements for the airborne thermal imaging spectrometer ARES

ARES (Airborne Reflective/Emissive Spectrometer) is an airborne imaging spectrometer for remote sensing of land surfaces covering the wavelength regions 0.45–2.45?µm and 8–13?µm with 160 channels. The instrument is being built by Integrated Spectronics, financed by DLR and GFZ, and will be available to the scientific community from 2005 on.

This contribution presents the design of the thermal spectrometer covering the 8–13?µm region with 32 channels of 150?nm bandwidth while a separate paper treats the instrument specifications in the solar reflective region. The spectro‐radiometric design is based on scientific requirements derived from application scenarios comprising vegetation, soils of different compositions, and mineral exploration. The corresponding emissivity spectra are input for a simulation model that calculates at‐sensor radiance spectra, resamples them with the channel‐specific response functions, adds different amounts of sensor noise to the signal, and performs a retrieval to get the corresponding noisy surface emissivity spectra. The results of the simulation study indicate that a spectral wavelength accuracy of 3?nm and a sensor noise equivalent temperature of 0.05–0.1?K are required for an accurate retrieval of emissivity spectra.     

Improving data fusion in personal positioning systems for outdoor environments

A fault detection and correction methodology for personal positioning systems for outdoor environments is presented. We demonstrate its successful use in a system consisting of a global positioning system receiver and an inertial measurement unit. Localization is based on the dead reckoning algorithm. In order to obtain more reliable information from data fusion, which is carried out with Kalman filtering, the proposed methodology involves: (1) evaluation of the information provided by the sensors and (2) adaptability of the filtering. By carefully analyzing these factors we accomplish fault detection in different sources of information and in filtering. This allows us to apply corrections whenever the system requires it. Hence, our methodology consists of two stages. In the first stage, the evaluation is conducted. We apply the principles of causal diagnosis using possibility theory by defining states for normal behavior and for fault states. When a fault occurs, corrective measures are applied according to empirical knowledge. In the second stage, the consistency test of the filtering is performed. If this is inconsistent, principles of adaptive Kalman filtering are applied, which means the process and measurement noise matrices are tuned. Our results indicate a reasonable improvement of the trajectory obtained. At the same time, we can achieve consistent filtering, to obtain a more robust system and reliable information.     

An extension of the Boyer-Moore Theorem Prover to support first-order quantification

We describe an implementation of an extension to the Boyer-Moore Theorem Prover and logic that allows first-order quantification. The extension retains the capabilities of the Boyer-Moore system while allowing the increased flexibility in specification and proof that is provided by quantifiers. The idea is to Skolemize in an appropriate manner. We demonstrate the power of this approach by describing three successful proof-checking experiments using the system, each of which involves a theorem of set theory as translated into a first-order logic. We also demonstrate the soundness of our approach.This research was supported in part by ONR Contract N00014-88-C-0454. The views and conclusions contained in this document are those of the author and should not be interpreted as representing the official policies, either expressed or implied, of Computational Logic, Inc., the Office of Naval Research or the U.S. Government.     

Routing in Polygons Without Rectilinearly Visible Corners

In this paper we present an algorithm for the routing problem in a routing region which is bordered by a simple polygonal line, such that there are no rectilinearly visible corners. The routing problem consists in finding pairwise edge-disjoint paths in the grid for the nets connecting some given pairs of boundary vertices. Whenever a solution exists our algorithm finds it in time O(U log²U), where U is the size of the boundary. This is a generalization of the algorithm for rectangle routing by Mehlhorn and Preparata (1986, J. Assoc. Comput. Mach.33, 60-85), which up to now has been the only method with sublinear running time in respect of the routing area.     

AlphaPilot: autonomous drone racing

Autonomous Robots - This paper presents a novel system for autonomous, vision-based drone racing combining learned data abstraction, nonlinear filtering, and time-optimal trajectory planning. The...     

Integrated cost/weight optimization of aircraft structures

A methodology for a combined cost/weight optimization of aircraft components is proposed. The objective function is formed by a simplified form of direct operating cost, i.e. by a weighted sum of the manufacturing cost and the component weight. Hence, the structural engineer can perform the evaluation of a design solution based on economical values rather than pure cost or weight targets. The parameter that governs the balance between manufacturing cost and weight is called weight penalty and incorporates the effect of fuel burn, environmental impact or contractual penalties due to overweight. Unlike previous work, the analytical cost model and structural models are replaced by commercially available software packages that allow a more realistic model of the manufacturing costs; further, arbitrary constraints for the structural analysis can be implemented. By means of parametric studies it is shown that the design solution strongly depends on the magnitude of the weight penalty.     

基于蓝牙的多机通信的实现及其应用

本文提出了一种基于蓝牙通信协议的PC机监控多台单片机控制系统的多机通信方案。针对蓝牙芯片PTR2000,对多机通信的设计方法、系统的组成原理进行了阐述;对上位机蓝牙接口电路、单片机蓝牙接口电路的实现过程进行了详细的说明;对蓝牙通信协议,特别是大数据传输协议进行了设计。以汉字传输过程为例,提出了一种提取汉字的点阵算法,对上下位机之间进行汉字传输的软件设计与实现过程进行了说明,对实验结果进行了分析。实验结果表明,上述通信方案是成功的和有效的。