Scharnhauser公园学校和体育馆,奥斯特菲尔登

这个综合学校包括一个主建筑,一个体育馆和各种户外设施,朝向一片处在前军事基地上的住宅开发区。整个主建筑沿纵向被一个由顶部采光的回廊从中间分开,由此可以进入两侧的教室,回廊局部变宽的部分构成一个公共空间。这个构想与将城市设计理论运用于建筑内部设计的概念相符合:街道、广场和建筑被看成了建筑内部空间部分。虽然这个建筑从外部看来是个大体块,但内部空间却设计流畅,通道有的通向楼层的各个角落,也有的依着倾斜的地势因势而建。由墙面反射的散射光线加强了内部空间的肃穆和厚重感。在具有宗教感的整体风格下,整个学校的设计和装饰也显得古香古色,如一部宽阔的观光楼梯、两个塔形和壁炉形的建筑构成元素等。不同历史风格建筑的叠加给这个校区带来一种复杂的味道,堪比阿尔多·罗西(Aldo Rossi)的设计或泰辛(Tessin)新理性主义的代表作。     

ON THE INVERTIBILITY OF PERIODIC MOVING-AVERAGE MODELS

Abstract. A sufficient condition for the invertibility of univariate periodic moving-average models has been given by Cipra and Ghysels and Hall. We show that this condition is not a necessary one, and provide a necessary and sufficient condition for the general m -variate, d -periodical moving-average MA( q ) case.     

Mistracking in successive PCM/ADPCM transcoders

An analysis is presented of the causes of the accumulation of quantizing noise found in the transient state for successive CCITT adaptive differential pulse-code-modulation (ADPCM) transcoders connected synchronously. By decoupling the predictor and quantizer effect it is proved that, owing to a self-stabilization phenomenon, narrowband inputs cause local instabilities in the predictor of the jointly adaptive autoregressive moving-average-prediction/quantization used in the ADPCM 32-kb/s algorithm. Despite the assured global stability, these local instabilities are not synchronized at the encoder and its preceding decoder, and a mistracking occurs which creates quantizing noise accumulation. The tracking is then shown to be very sensitive to predictor/quantizer interaction. The discontinuities introduced in the standardized adaptive quantizer extend the mistracking problem to wideband inputs. A smoothed quantizer with reduced inauspicious interaction is proposed to remedy the problem     

Elastomeric alloys of PVC

The performance standards for flexible PVC compounds continue to become more demanding as manufacturers pursue more value-added applications traditionally dominated by rubbers and thermoplastic elastomers. Blending of PVC with other polymers has proven to be a viable approach in developing higher performance flexible PVC-based materials. This paper will review some of the typical approaches to producing PVC-based elastomers, and show how these standard flexible PVC blends compare to a newly developed family of PVC alloys. The advantages of these materials will be discussed, and some examples of commercial materials and their application will also be reviewed.     

Exploiting partial or complete geometrical symmetry in 3D symmetric Galerkin indirect BEM formulations

Procedures based on group representation theory, allowing the exploitation of geometrical symmetry in symmetric Galerkin BEM formulations, are investigated. In particular, this investigation is based on the weaker assumption of partial geometrical symmetry, where the boundary has two disconnected components, one of which is symmetric; e.g. this can be very useful for defect identification problems. The main development is expounded in the context of 3D Neumann elastostatic problems, considered as model problems; and then extended to SGBIE formulations for Dirichlet and/or scalar problems. Both Abelian and non‐Abelian finite symmetry groups are considered. The effectiveness of the present approach is demonstrated through numerical examples, where both partial and complete symmetry are considered, in connection with both Abelian and non‐Abelian symmetry groups. Copyright © 2003 John Wiley & Sons, Ltd.     

A reactive molecular dynamics model of thermal decomposition in polymers: I. Poly(methyl methacrylate)

The theory and implementation of reactive molecular dynamics (RMD) are presented. The capabilities of RMD and its potential use as a tool for investigating the mechanisms of thermal transformations in materials are demonstrated by presenting results from simulations of the thermal degradation of poly(methyl methacrylate) (PMMA). While it is known that depolymerization must be the major decomposition channel for PMMA, there are unanswered questions about the nature of the initiation reaction and the relative reactivities of the tertiary and primary radicals formed in the degradation process. The results of our RMD simulations, performed directly in the condensed phase, are consistent with available experimental information. They also provide new insights into the mechanism of the thermally induced conversion of this polymer into its constituent monomers.     

Design and architecture of a new space priority mechanism for ATM network nodes

This paper presents the architecture of a new space priority mechanism intended to control cell loss in ATM switches. Our mechanism is a new generic concept called: the multiple pushout. It is based on the utilization of both AAL and ATM features and on a particular definition of the priority bit. Whenever one cell of a message overflows the buffer of an ATM switch, the algorithm causes the switch to discard other cells of the message (including later arrivals). Such discarding frees buffer spaces for cells of other messages that have a chance of arriving at their destination intact. Our objective is to emphasize that in case of overload, with most of proposed mechanisms, cells are discarded without any semantic information about the type of cells. Therefore, at the destination, all the fragments of the corrupted messages will be discarded anyway. Finally, we present simulation results comparing cell loss rates and message loss rates of several space priority mechanisms.     

基于SIP的新一代电信业务

第二代(2G)移动网络和传统的固定网络都提供了一套相对完整的话音业务。尽管智能网络(IN)技术使电信业务有所增强,但电信业务的发展仍然缓慢,而且样式基本保持不变。下一代网络(NGN)和第三代(3G)移动网络就是为了克服这些局限性而设计的,它们通过重组网络架构将业务同网络分离开来、将信息和电话技术融合起来并引进了会话初始协议(SIP)等开放协议。同时,它们还有望提供满足用户和运营商需求的新的增值业务。这些网络包括满足用户对业务期望所需的所有组成部分。NGN和3G就其服务能力而言有3个主要优点:首先,它们将信息世界和电话世界结…