Key management for decentralized computer network services

The authors propose an efficient scheme for key management, incorporating smart card technology and the master key concept, for both users and providers in multiservice environments over a large-scale network. This scheme has the following features. Every service can handle its own authentication and administration. Every user has a smart card with a single master key. The service keys can be regenerated within the card in a very secure manner. Users can also update their master keys by themselves without third-party intervention. As there is no need for storing any user password in the service center (except, perhaps, for a user PIN number), security is greatly enhanced     

A non-repudiation metering scheme

A metering scheme enables a Web server to measure the number of visits from clients. In addition, a proof needs to be presented by the server as evidence corresponding to this measured number. In this letter, we propose an efficient metering scheme that incorporates the hash-chaining technique and the digital signature algorithm to provide a nonrepudiation proof of this measured number     

Molecular cloning of starch synthase I from maize (W64) endosperm and expression in Escherichia coli

Vertebrate myelin is enriched in the lipid galactocerebroside (GalC) and its sulfated derivated sulfatide. To understand the in vivo function of these lipids, we analyzed myelination in mice that contain a null mutation in the gene encoding UDP-galactose:ceramide galactosyltransferase, the enzyme responsible for catalyzing the final step in GalC synthesis. Galactolipid-deficient myelin is regionally unstable and progressively degenerates. At postnatal day 30, demyelination is restricted to the midbrain and hindbrain, but by postnatal day 90, it spreads throughout the central nervous system. Activated microglial cells and reactive astrocytes appear with the loss of myelin in older animals. Nonetheless, major myelin protein gene mRNA levels are normal throughout the life of these animals, suggesting that widespread oligodendrocyte death is not the primary cause of demyelination. The developmental switch in myelin-associated glycoprotein isoform expression, however, does not occur normally in these mice, suggesting an alteration in oligodendrocyte maturation. Taken together, these findings indicate that GalC and sulfatide are required for the long-term maintenance of myelin and that their absence may have subtle effects on the development of oligodendrocytes.     

使用紧耦合协处理器进行算法加速

引言 在现场可编程门阵列的早期阶段,FPGA主要被用作芯片与芯片通信的接合逻辑或其他桥接类型的功能.现在的FPGA器件解决方案包含了完整的嵌入式处理器和处理子系统.设计人员要求在处理性能、新特性内容和降低成本等方面不断提高.随着对性能改善的要求进一步提高,FPGA固有的并行性提供了通过紧耦合协处理器实现硬件重大加速从而提升性能的独特能力.这在设计计算密集型应用时尤其重要.可从此类算法加速中获益的系统包括无线通信与图像处理平台,如在医疗、视频和其他图形应用中所见到的那些系统,它们需要大量的信号处理.     

Computation-efficient key establishment in wireless group communications

Wireless Networks - Efficient key establishment is an important problem for secure group communications. The communication and storage complexity of group key establishment problem has been studied...     

Tendenzen der MDF-Plattenerzeugung

Ohne Zusammenfassung     

Task‐based conceptual graphs as a basis for automating software development

It is widely recognized that requirements engineering is a knowledge‐intensive process and cannot be dealt with using only a few general principles. Since knowledge plays a crucial role in software development, software engineers have to describe and organize various aspects of knowledge before the program can be written. A recent work by Robillard reveals that software development can be further improved by recognizing the relevant knowledge structures. In this paper, we propose the use of a task‐based conceptual graphs (TBCB) framework as a basis for automating software development. By structuring and operationalizing conceptual graphs, TBCG specifications can be transformed into executable programs automatically. To construct a conceptual model, task‐based specification methodology is used as the mechanism to structure the knowledge captured in conceptual models, whereas conceptual graphs are adopted as the formalism to express task‐based specifications and to provide a reasoning capability for the purpose of automation. Once task‐based graphs have been constructed and verified, a blackboard system will automatically transform TBCG specifications into a software system composed of database schemas, knowledge base, and user interfaces. A meeting scheduling system is used as an illustrative example to demonstrate our approach. © 2000 John Wiley & Sons, Inc.     

Candidate vaccine antigens that stimulate the cellular immune response of mice vaccinated with irradiated cercariae of Schistosoma mansoni

Vaccination with radiation-attenuated cercariae confers the highest levels of resistance to challenge infection in experimental schistosomiasis and requires Ag-specific T cells. Therefore, this study aimed to identify specific Ag that stimulate the cellular immune response of mice vaccinated with irradiated cercariae of Schistosoma mansoni. Four experimental groups representing different levels of resistance in the vaccine model (C57BL/6J versus CBA/J mice vaccinated with 15- or 50-krad irradiated cercariae) were compared for in vitro lymphocyte proliferation and lymphokine production. Adult worm extracts fractionated by isoelectric focusing were used as Ag. Lymphocyte proliferation of all groups was limited to three consecutive isoelectric fractions (pH 4.6-6.3). Interestingly, the antibody response of these mice was directed to Ag in the same isoelectric fractions, three of which had previously been identified as paramyosin, heat shock protein 70, and the integral membrane protein Sm23. These Ag as well as two 28 kDa proteins, triosephosphate isomerase and glutathione S-transferase, in purified native or recombinant form or as a synthetic peptide, stimulated lymphocyte proliferation. Lymphocytes of vaccinated C57BL/6J mice generally showed higher levels of proliferation than did CBA/J mice. Interestingly, cells of once-vaccinated mice responded better than did cells of mice vaccinated three times. Lymphokine assays demonstrated that IL-2 and IL-4 was generally reduced after multiple vaccinations and varied qualitatively as well as quantitatively between mouse strains. This study substantiates that the five Ag, paramyosin, heat shock protein 70, triosephosphate isomerase, glutathione S-transferase, and the integral membrane protein Sm23, are important candidates for a defined antischistosomal vaccine.     

Growth of transplanted tumours in mice treated with macrophages and their products

The antitumour activity of peritoneal macrophages, added to tumour inocula (Winn test), was determined. Macrophages harvested from mice immunised with tumour, or from tumour-bearing mice, suppressed or inhibited tumour growth when in direct contact with tumour cells. Incubation of macrophages exhibiting antitumour activity with tumour cells yielded supernatant fluids capable of interfering with tumour growth. Consistent induction of antitumor activity required either addition of indomethacin to the incubation mixture, or collection of macrophages from immunised or tumour-bearing donors that had ingested indomethacin in the drinking water. Tumour growth was significantly inhibited when tumour inocula were suspended in supernatant fluid, or when mice were given several subcutaneous injections of supernatant prior to tumour transplantation.     

Interdisciplinary question generation: Synthesis and validity analysis of the 1993–1997 bovine mastitis-related literature

Interdisciplinary synthesis and validity analysis (ISVA), a structured learning approach which integrates learning and communication theories, meta-analytic evaluation methods, and literature management-related technologies was applied in the context of the 1993–1997 bovine mastitis research literature. This study investigated whether ISVA could: 1) facilitate the analysis and synthesis of interdisciplinary knowledge claims, and 2) generate projects or research questions. The bovine mastitis-related literature was conceptualized as composed of microbiological, immunological, and epidemiological dimensions. Keywords involving these dimensions were searched in theMedline andAgricola databases. A final list of 148 articles were retrieved, analyzed, synthesized into fifteen information sub-sets, and evaluated for construct, internal, external and statistical validity through an interdisciplinary iterative dialogical process. Validity threats were re-phrased as new research or educational projects.