Interactive blood-coil simulation in real-time during aneurysm embolization

Over the last decade, remarkable progress has been made in the field of endovascular treatment of aneurysms. Technological advances continue to make it possible for a growing number of patients with cerebral aneurysms to be treated with a variety of endovascular strategies, essentially using detachable platinum coils. Yet, coil embolization remains a very complex medical procedure for which careful planning must be combined with advanced technical skills in order to be successful. In this paper, we describe a complete process for patient-specific simulations of coil embolization, from mesh generation with medical datasets to computation of coil-flow bilateral influence. We propose a new method for simulating the complex blood flow patterns that take place within the aneurysm, and for simulating the interaction of coils with this flow. This interaction is twofold, first involving the impact of the flow on the coil during the initial stages of its deployment, and second concerning the decrease of blood velocity within the aneurysm, as a consequence of coil packing. We also propose an approach to achieve real-time computation of coil-flow bilateral influence, necessary for interactive simulation. This in turns allows to dynamically plan coil embolization for two key steps of the procedure: choice and placement of the first coils, and assessment of the number of coils necessary to reduce aneurysmal blood velocity and wall pressure. Finally, we provide the blood flow simulation results on several aneurysms with interesting clinical characteristics both in 2D and 3D, as well as comparisons with a commercial package for validation. The coil embolization procedure is simulated within an aneurysm, and pre- and post-operative status is reported.     

Dynamic demultiplexing in network calculus—Theory and application

During the last two decades, starting with the seminal work by Cruz, network calculus has evolved as a new theory for the performance analysis of networked systems. In contrast to classical queueing theory, it deals with performance bounds instead of average values and thus has been the theoretical basis of quality of service proposals such as the IETF’s Integrated and Differentiated Services architectures. Besides these it has, however, recently seen many other application scenarios as, for example, wireless sensor networks, switched Ethernets, avionic networks, Systems-on-Chip, or even to speed-up simulations, to name a few.In this article, we extend network calculus by adding a new versatile modeling element: a demultiplexer. Conventionally, demultiplexing has been either neglected or assumed to be static, i.e., fixed at the setup time of a network. This is restrictive for many potential applications of network calculus. For example, a load balancing based on current link loads in a network could not be modeled with conventional network calculus means. Our demultiplexing element is based on stochastic scaling. Stochastic scaling allows one to put probabilistic bounds on how a flow is split inside the network. Fundamental results on network calculus with stochastic scaling are therefore derived in this work. We illustrate the benefits of the demultiplexer in a sample application of uncertain load balancing.     

Corrected upper bounds for free-cut elimination

Free-cut elimination allows cut elimination to be carried out in the presence of non-logical axioms. Formulas in a proof are anchored provided they originate in a non-logical axiom or non-logical inference. This paper corrects and strengthens earlier upper bounds on the size of free-cut elimination. The correction requires that the notion of a free cut be modified so that a cut formula is anchored provided that all of its introductions are anchored, instead of only requiring that one of its introductions is anchored. With the correction, the originally proved size upper bounds remain unchanged. These results also apply to partial cut elimination. We also apply these bounds to elimination of cuts in propositional logic.If the non-logical inferences are closed under cut and infer only atomic formulas, then all cuts can be eliminated. This extends earlier results of Takeuti and of Negri and von Plato.     

面向行动的信念更新

基于可能模型方法 ( possible m odel approach,简称 PMA) ,提出了面向行动的信念更新的概念 ,证明了在信息完备的情境演算系统中 ,一个一阶公式在情境 s下成立当且仅当它属于情境 s下的信念集 .这一结果为有效避免情境演算推理中二阶归纳公理的使用提供了一条可行的途径 ,也为基于意向驱动的 agent模型的建立以及面向 agent的程序设计语言 AOPL ID( agent-oriented programm ing language with intention driver)的提出提供了必要的理论基础.     

多Agent系统中基于Rough集的推理

定义了多Ａｇｅｎｔ系统中的推理模型,建立了在该模型下的Ｒｏｕｇｈ集和基于Ｒｏｕｇｈ信方法的Ｒｏｕｇｈ包含计算或称集合连接计算,在知识发现和数据挖掘中,集合之间往往不是给出它们的相等性,而是讨论它们之间的Ｒｏｕｇｈ包含或连接。因为在不同的Ａｇｅｎｔ中集合之间关系的精确和一致解释往往是不容易获得的。一般说来,一条基于决策表上的规则,满足前提公式个体的集合包含于满足结论公式个体的集合常常是用一种支持值和     

多主体间的协作过程研究

多主体间的协作是多主体系统与其它相关研究领域区别开来的关键性概念之一,也是保证多个智能系统在一起共同工作的关键,将规划、竞争、约束、及协调纳入一个协作框架之中对多主体间的协作过程进行了研究,并将协作过程分为①产生需求、确定目标;②协作规划、妥协作结构;③寻求协作伙伴;④选择协作方案;⑤实现目标;⑥评估结果等６个阶段,地规范描述主体间的协作行为时,还将逻辑和进程代数方法巧妙地融进了一个统一的形式化框     

A functional presentation of Pi calculus

From the very beginning process algebra introduced the dichotomy between channels and processes. This dichotomy prevails in all present process calculi. The situation is in contrast to that withlambda calculus which has only one class of entities-the lambda terms. We introduce in this papera process calculus called Lamp in which channels are process names. The language is more uniform than existing process calculi in two aspects-. First it has a unified treatment of channels and processes.There is only one class of syntactical entities-processes. Second it has a unified presentation ofboth first order and higher order process calculi. The language is functional in the sense that lambda calculus is functional. Two bisimulation equivalences, barbed and closed bisimilarities, are proved to coincide.A natural translation from Pi calculus to Lamp is shown to preserve both operational and algebraic semantics. The relationship between lazy lambda calculus and Lamp is discussed.     

Optimal Control for Partially Observed Nonlinear Deterministic Systems with Fuzzy Parameters

In this paper we consider the control problem for a class of partially observed deterministic systems governed by nonlinear differential equations with fuzzy parameters. Using Takagi–Sugeno fuzzy model, we propose a linear (fuzzy) controller, driven by the output process, for controlling the system. Further, using calculus of variations, we have developed a set of necessary conditions on the basis of which optimal control can be determined. Based on these necessary conditions we have proposed a numerical algorithm for computing optimal control along with some numerical simulations to illustrate the effectiveness of the proposed (fuzzy) control scheme.     

并发面向对象语言COOLⅡ的语义模型

缺乏好的形式化语义模型使得并发面向对象语言的开发受到了很大的影响,本文设计了并发面向对象LISP语言COOLⅡ,给出了该语言的语法、基于配置的操作语义,并提出了并发对象演算CONOC,以此为基础讨论了COOLⅡ的变换语义。