Deriving protocol specifications from service specifications written in LOTOS

Summary.  A complete communication system is broken down into a number of protocol layers each of which provides services to the layer above it and uses services provided by its underlying layer. A service specification defines a particular ordering of the operations that a given layer provides to the layer above it. The active elements in each layer are called entities and they use a protocol in order to implement their service definition. On the basis of this relation between the service and protocol concepts we have developed algorithms for deriving protocol entity specifications from a formal service specification. The derived protocol entities ensure the correct ordering of the service primitives by exchanging synchronization messages through an underlying communication medium. This paper presents an extended version of our earlier derivation algorithms. This version of the algorithm can handle all operators and unrestricted process invocation and recursion as defined by basis LOTOS. The correctness of this derivation algorithm is formally proved. Received: January 1992 / Accepted: February 1996     

Passive Grubenwasserreinigung als Alternative zu aktiven Systemen

Um kontaminiertes Grubenwasser langfristig kostengünstig reinigen zu k?nnen, sind Methoden mit geringstm?glichen Investitions- und Unterhaltungskosten n?tig. Dazu wurden in Gro?britannien und Deutschland in den zurückliegenden Jahren unterschiedliche passive Reinigungssysteme in Betrieb genommen (z. B. anoxische Karbonatkan?le, konstruierte Feuchtgebiete, reaktive Barrieren, Gro?oberfl?chenfilter).     

Tree automata for code selection

We deal with the generation of code selectors in compiler backends. The fundamental concepts are systematically derived from the theory of regular tree grammars and finite tree automata. We use this general approach to construct algorithms that generalize and improve existing methods.Funded by the ESPRIT Project #5399 (COMPARE)Funded by DFG SFB #124 VLSI-Design and Parallelism     

BMP-4 is proteolytically activated by furin and/or PC6 during vertebrate embryonic development

Bone morphogenetic protein-4 (BMP-4) is a multifunctional developmental regulator. BMP-4 is synthesized as an inactive precursor that is proteolytically activated by cleavage following the amino acid motif -Arg-Ser-Lys-Arg-. Very little is known about processing and secretion of BMPs. The proprotein convertases (PCs) are a family of seven structurally related serine endoproteases, at least one of which, furin, cleaves after the amino acid motif -Arg-X-Arg/Lys-Arg-. To examine potential roles of PCs during embryonic development we have misexpressed a potent protein inhibitor of furin, alpha1-antitrypsin Portland (alpha1-PDX) in early Xenopus embryos. Ectopic expression of alpha1-PDX phenocopies the effect of blocking endogenous BMP activity, leading to dorsalization of mesoderm and direct neural induction. alpha1-PDX-mediated neural induction can be reversed by co-expression of downstream components of the BMP-4 signaling pathway. Thus, alpha1-PDX can block BMP activity upstream of receptor binding, suggesting that it inhibits an endogenous BMP-4 convertase(s). Consistent with this hypothesis, alpha1-PDX prevents cleavage of BMP-4 in an oocyte translation assay. Using an in vitro digestion assay, we demonstrate that four members of the PC family have the ability to cleave BMP-4, but of these, only furin and PC6B are sensitive to alpha1-PDX. These studies provide the first in vivo evidence that furin and/or PC6 proteolytically activate BMP-4 during vertebrate embryogenesis.     

Real Voices in the Technological Wilderness Using ethnographic methods to challenge global wireless paradigms

This paper explores the use of ethnographic research to help companies design, build, and implement products and services that meet the stated and unstated needs of consumers. Although many products enjoy an international presence in the global economy, the market is far from homogeneous. Cultural practices and beliefs strongly influence the meaning and, consequently, the usage of products. If a product is not culturally resonant, the product may not be adopted by consumers - no matter how technologically advanced or innovative the product may be. Specifically, this paper explores mobile phone, and advanced network I-mode adoption in Japan. Research methodologies used in the case study are described, including how these techniques elucidate the various social and cultural processes that influence adoption. In order to develop wireless and other mobile communication solutions that are culturally, emotionally, and technically satisfying for users, the current “ global paradigm” must be reconsidered. Incorporating anthropology into the design process is a crucial first step in helping telecommunication companies define their next generation of products and services in the mobile communications arena.     

Technische Möglichkeiten und Akzeptanz mobiler Anwendungen

Mobile data communication applications, referred to in this paper as mobile applications, were one of the technological innovation and investment targets in recent years. From the past it became obvious that mono-disciplinary approaches to investigate mobile applications have shortcomings when it comes to successful innovation and investment decisions as interdependencies are insufficiently addressed. The paper therefore aims at structuring the scientific contributions of computer science, business economics and sociology in the context of mobile applications to approximate a holistic understanding comprising technological feasibility, economic opportunities and human needs.     

SMART(R)/ASTC技术在连铸冶金操作和经济诸方面的效益

与SMART~(R)扇形段技术配合使用的自动控制铸坯锥度(ASTC)的发展和应用,减少了中心偏析,使铸坯内部质量得到明显改进。遥控调整辊缝锥度和动态轻压下的应用,也能满足瞬间浇铸条件的特殊要求。到2003年5月止,在芬兰、美国、意大利、奥地利、韩国和中国共有9台11流板坯连铸机使用SMART~(R)/ASTC技术进行操作。另外,还有7台18流其它类型的连铸也已订购采用这项技术。SMART~(R)/ASTC技术对于在板坯和大方坯连铸机上浇铸所有的钢种都很理想。在大方坯连铸机上应用的实例是计划安装在中国攀枝花钢铁集团的6流大方坯连铸机。     

Constellation Rearrangement: Enhancement for Multilevel Modulation Formats and Transmit Diversity

Radio link adaptivity will be a key feature of the air interfaces of future mobile communication systems. This adaptivity includes techniques such as fast scheduling, hybrid ARQ, transmit diversity and adaptive modulation and coding. The performance of adaptive modulation generally suffers from the power inefficiencies of multilevel modulation formats. This is due to the variations in bit reliabilities caused by the bit-mapping onto the signal constellation. This article presents a concept, called constellation rearrangement (CoRe), which improves the multilevel modulation power efficiency by the joint application with transmit diversity schemes. It is shown by a theoretical analysis for 16-QAM that the presented concept can equalize variations in bit reliabilities by employing different mapping rules for the transmission over the diversity branches. This significantly improves the receiver block error rate performance and, hence, the performance of the adaptive modulation and coding. This is proven by simulations at link-level in a multicarrier CDMA system for AWGN and fading channels employing turbo coded transmission.