一种用于线阵列系统极性测试的可靠方法

一组线阵列系统的性能在很大程度上取决于其扬声器的正确安装。例如,一个极性错误的单体扬声器可能会明显地影响整个系统的声压和指向性。然而,这种错误的鉴定非常耗时。因此,这就需要一种快速同时又可靠的方法来找出这样的线阵元素。介绍了一种怎样一步一步来检查一个完整的线阵列系统的方法,同时,还能找出引起极性问题的原因。除了理论背景,还描述了一个实际应用的成功案例。     

Synthesis and characterization of maghemite nanosheets

Magnetic maghemite nanoparticles in the form of nanosheets were prepared by a topotactic transformation during the dehydroxylation of a γ-FeO(OH) precursor. The precursor was synthesized from tetrapyridin Fe(II) chloride (Fe(py)₄Cl₂). The nanosheets are several hundreds of nanometers wide, and less than 5 nm thick; they frequently bend and curl at the edges; they are nanocrystalline; and they are composed of smaller maghemite nanostructured domains, from a few nanometers up to several tens of nanometers wide.     

The calculus of context relations

We present the theory of context relations. Context relations are a method for incremental semantic analysis in language-specific editors, which is able to handle incomplete program fragments. The algorithm is generated from the definition of a language's static semantics and is based on inference rules and order-sorted unification. The paper presents the underlying mathematical theory, optimal incremental analysis algorithms, handling of user-defined polymorphism and overloading, and implementation issues. It is intended as the concluding report on a by now mature concept, which has successfully been used to generate efficient incremental type inferencers for languages like ADA and Fortran 8x.     

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     

A formal method for synthesizing optimized protocol converters and its application to mobile data networks

As mobile information networks are expanding rapidly, we expect to integrate voice, paging, electronic mail and other wireless information services. Interworking units that perform protocol conversion at the boundaries of different networks will play an important role. In this paper, we propose an efficient algorithm for constructing optimized protocol converters to achieve interoperability between heterogeneous data networks. This algorithm first derives constraints from two given protocols, and apply the constraints to channel specifications, thus removing message sequences that do not contribute to system progress. Then, an optimized converter is generated from a given service specification, the two protocol specifications and the modified channel specifications. A reduction relation is used to compare the service specification and the constructed internetworking system in order to deal with the problem of nondeterministic services. Compared with related works, our method has two advantages: (1) it generates an optimized converter; (2) it can be applied to the case that the service specification is nondeterministic. The application of the method to mobile networks is given by an example. This revised version was published online in June 2006 with corrections to the Cover Date.     

A possible defective estimation of antineutrophil cytoplasmic antibodies in systemic lupus erythematosus due to the coexistence of periodontitis: preliminary observations

The Family Environment Scale has been used extensively in family research since first being published. However, despite its appeal both conceptually and empirically, doubts have been raised over the scale's reliability. This article presents normative and reliability data for the Family Environment Scale from a large, combined sample of adolescents. Means and standard deviations were generally found to be in line with those reported in the scale's manual; however, estimates of internal consistency for most subscales could be considered inadequate for research purposes.     

A theory of industry-level activity for understanding the adoption of interorganizational systems

Increasingly we wish to ask and research questions about the adoption of interorganizational systems and electronic commerce at the industry level but are hampered by the lack of a theory of concerted purposeful action at this large level of analysis. In this paper we give the outlines of such a theory and indicate the uses to which it can be put. Particular attention is paid to how the routine day-to-day activities of the firms and support organizations that make up an industry group can be coordinated in such a way that we can speak of an industry as engaged in purposeful activity. We contend that only through a deep understanding of the possibilities and nature of routine coordinated activity at this level can issues concerning promotion, implementation and adoption of interorganizational systems by whole industries be properly framed.     

Retinal vascular changes in congenital hypertrophy of the retinal pigment epithelium

The overlying retinal blood vessels were abnormal in five cases of congenital hypertrophy of the retinal pigment epithelium. This illustrated the well-recognized association between outer retinal degeneration and obliteration of the overlying retinal vasculature. The proposed pathophysiological mechanisms, however, seem inadequate to explain completely the morphological changes of the retinal blood vessels in the presence of atrophy of the outer retina.