Numerical simulation of contaminant transport in groundwater using software tools of $$r^3t$$

When a realistic modelling of radioactive contaminant transport in flowing groundwater is required, very large systems of coupled partial and ordinary differential equations can arise that have to be solved numerically. For that purpose, the software package \(r^3t\) is developed in which several advanced numerical methods are implemented to solve such models efficiently and accurately. Using software tools of \(r^3t\) one can treat successfully nontrivial mathematical problems like advection-dominated system with different retardation of transport for each component and with nonlinear Freundlich sorption and/or precipitation. Additionally, long time simulations on complex 3D geological domains using unstructured grids can be realized. In this paper we introduce and summarize the most important and novel features of numerical simulation for radioactive contaminant transport in porous media when using \(r^3t\).     

Retrospective analysis for evaluation of the value of contrast-enhanced MRI in patients treated with breast conservative therapy

Purpose The aim of this study was to assess the value of contrast-enhanced (c.-e.) MRI in the follow-up of patients with conservatively treated breast cancer since detection and exclusion of malignancy may interfere significantly with posttherapeutic changes within the treated breast. Material and methods A total of 207 patients with a history of limited surgery and radiation therapy underwent MR imaging, 40 patients were examined 0–12 months and 167 patients were examined later than 12 months after radiotherapy. Suspicious or indeterminate findings were suggested by clinical examination or conventional imaging in 80 studies. In 127 women, MRI was performed within breast tissue that was difficult to assess due to scarring or dense breast tissue. Results Recurrent carcinoma was confirmed in 27 patients by surgical biopsy. All 27 carcinomas, except for one with a slow signal increase, demonstrated early rise of signal intensity on dynamic T1-weighted contrast enhanced images. During the first year after therapy, the diagnostic accuracy could not be improved by additional use of c.-e. MRI. Differentiation between posttherapeutic changes and recurrent carcinoma was frequently not possible because of strong and sometimes early and ill-circumscribed enhancement. Later than 12 months after therapy enhancement decreased significantly, thus the false positive calls could be reduced from 49 (conventional imaging) to 12 (conventional imaging plus MRI). A total of 12 of 26 recurrences and multifocality in 4/5 cases were diagnosed by MR imaging alone at this time interval. Conclusion In the first year after therapy, c.-e. MRI is only indicated in selected cases. The results later than 12 months emphasize that c.-e. MRI may contribute significant additional information. It allows better distinction of posttherapeutic fibrosis from recurrent carcinoma and proved to be able to detect recurrent disease more sensitive and at an earlier stage.     

MeeGo：将开源进行到底

MeeGo,正在成为移动直联网领域的一颗新星。 在今年2月的世界3GSM大会上,诺基亚与英特尔一起宣布了新一代专门针对移动终端的智能操作平台——MeeGo的诞生。MeeGo是英特尔的Moblin与诺基亚的Maemo的组合体,是为下一代计算设备打造的基于Linux系统的开源软件平台,它完全开放源代码,能够将服务、内容与用户体验相结合,为消费者带来全新的移动互联的操作体验。目前MeeGo由国际非盈利性组织Linux基金会进行管理。     

The Shopping Jacket: Wearable computing for the consumer

As part of the Bristol Wearable Computing Initiative, we are exploring location-sensing systems suitable for use with wearable computing. In this paper we present our findings, and in particular a wearable application — the ‘Shopping Jacket’ — which relies on a minimal infrastructure to be effective. We use two positioning devices, ‘pingers’ and GPS. The pinger is used to signal the presence of a shop, and to indicate the type of shop and its website. The GPS is used to disambiguate which branch of a high street chain is being passed. The wearable uses this information to determine whether the wearer needs to be alerted that they are passing an interesting shop, or to direct the wearer around a shopping mall. The Shopping Jacket integrates a wearable CardPC, GPS and pinger receivers, a near-field radio link, hand-held display, GSM data telephone and a speech interface into a conventional sports blazer.     

Euclidean controllable realizations of linear hereditary systems

A realization problem for a class of linear hereditary systems is formulated and state space representations are constructed from inputoutput relations. The resulting hereditary models are shown to be Euclidean controllable, and comparisons are made between these hereditary realizations and other recently developed theories.This research was supported in part by the Air Force Flight Dynamics Laboratory under grant AFOSR-77-3221.     

H 2-optimization and fixed poles of sampled-data systems with generalized hold functions and delay

A frequency-polynomial H ₂-optimization method for sampled-data systems with generalized hold functions and delay is proposed, which is based on the application of the concept of a parametric transfer matrix. A number of general properties of H ₂-optimal systems that must be taken into account in solving practical design problems are established.     

H 2-optimization and fixed poles for sampled-data systems with generalized hold

Standard multivariable sampled-data system with generalized hold of arbitrary order is investigated. An algorithm for design of H ₂-optimal digital controller is presented. Some qualitative properties of the H ₂-optimal system are described, which are important in applications.     

Planning in the Ethno-culturally Diverse City: A Comment

This article examines how major retailers, in their attempts to secure sites for very large stores (over 7000 m2 sales area), have had to adopt new strategies in order to overcome resistance from local authority and central government retail planning policy. These strategies include recycling of old retail developments with ‘open A1 consent’, participation in urban regeneration projects and development or redevelopment of ‘district shopping centres’ in urban areas. Discussion of these strategies reveals weaknesses and inconsistencies in retail planning policy in the UK.     

苏格兰小城镇：面临威胁的遗产

作为英国的一部分,苏格兰拥有其地方议会以及大量小城镇。在国际经济形势变化的冲击下,由于缺乏国家和地方政府的持续关注以及自身的某些局限性,苏格兰小城镇正面临重大挑战。尤其是那些位于偏远地区并失去传统产业支柱的小城镇,表现出较高的脆弱性。小城镇遗产保护是环境更加可持续发展的重要组成部分。创新性再定位,以及苏格兰建筑环境论坛提出的＂小城镇体检＂,为小城镇保护提供了新的思路和方法。