Performance of PKI-based security mechanisms in mobile ad hoc networks

Security for ad hoc network environments has received a lot of attention as of today. Previous work has mainly been focussing on secure routing, fairness issues, and malicious node detection. However, the issue of introducing and conserving trust relationships has received considerably less attention. In this article, we present a scalable method for the use of public key certificates and their revocation in mobile ad hoc networks (MANETs). With the LKN-ad hoc security framework (LKN-ASF) a certificate management protocol has been introduced, bringing PKI technology to MANETs. In addition a performance analysis of two different revocation approaches for MANETs will be presented.     

Role of Perceived Importance in Intergroup Contact.

Furthering G. W. Allport's (1954) contentions for optimal contact, the authors introduce a new construct: the perceived importance of contact. They propose that perceived importance is the best proximal predictor of contact's reduction of prejudice. If individuals have opportunities for contact at work or in the neighborhood, their chances to have intergroup acquaintances and friends increase. Intergroup contact among acquaintances and friends can be perceived as more or less important, which in turn determines intergroup evaluations. A 1st study shows that the new measure of perceived importance is indeed distinct from established quantity and quality indicators. The results are cross-validated in a 2nd study that also sheds light on the meaning of importance. In 3rd and 4th studies, structural equation analyses and a meta-analysis support the hypotheses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A formal description of open distributed processing (ODP) trading based on guidelines for the definition of managed objects (GDMO)

New requirements of growing computer networks and information systems have an influence on extended client/server models with increased functionality. This forms the basis for service management in distributed systems which is realized by a service trading concept. This paper studies the requirements derived from the Open Distributed Processing (ODP) Reference Model in order to consider an open service market. Furthermore, it examines management possibilities for describing the service trading scenario. Because of similar architectures and properties ODP services, service offers, types, exporters and traders are mapped onto management components and modeled as managed objects. Therefore, the Guidelines for the Definition of Managed Objects (GDMO) are used. The final concept allows a precise and unambiguous study of the service trading scenario and provides means for exporting and importing of service offers in a distributed environment.     

Psychology and the threat of nuclear war.

Discusses what is known about the effect of nuclear war on survivors' behavior, the effect of the threat of nuclear war, reducing the threat of nuclear war, and psychology's role in reducing the threat of nuclear war. It is concluded that although psychology has a certain level of understanding of the causes and consequences of nuclear war, its ability to provide counsel is limited. (55 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Studies on the sample weight for ochratoxin A determination in raw coffee

Ochratoxin A is a mycotoxin that may cause damage to the kidneys and the immune system in man. Foods are examined for this contaminant by the laboratories responsible for official food control. At present, there are no specific provisions for the sampling and examination of ochratoxin A in foods. Therefore, recourse is made to the provisions for aflatoxins. They prescribe the processing of samples with a weight of up to 30 kg. The examination of raw coffee for ochratoxin A in conjunction with the German Food Monitoring Programme of 2000 was undertaken with various sample weights (5, 10 and 30 kg) in order to identify the influence of the sample weight on the result. Overall, the sample weight did not have an effect on the detection and level of the ochratoxin A content in the samples of raw coffee examined.     

Is there a direct relationship between oral astringency and human salivary protein binding?

For decades, it is believed that astringency is due to the polyphenol-induced complexation of proline-rich salivary proteins in the oral cavity. In order to compare for the first time the human sensory threshold concentrations and the salivary protein binding activity of a series of astringent stimuli, human saliva protein was incubated for 5 min at 37 °C in the presence of astringent food-derived compounds and, after micro-centrifugation, the amount of the target molecules in the supernatant was quantitatively determined by HPLC-UV/Vis. Significant protein binding was observed for (−)-epigallocatechin-3-gallate, (−)-gallocatechin-3-gallate, (+)-gallocatechin, and (−)-catechin-3-gallate, all of which containing at least one galloyl moiety in the molecule and exhibiting rather high sensory thresholds of more than 200 μmol/L. In comparison, (+)-catechin and procyanidin B2, both lacking in any galloyl function, showed only comparatively low binding activity and, most interestingly, quercetin-3-O-α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside and 3-carboxymethyl-indole-1-N-β-d-glucopyranoside did not show any protein binding at all, although the later N- and O-glycosides exhibited extraordinarily low sensory threshold concentrations of less than 0.001 and 0.0003 μmol/L, respectively. The data give some first evidence that the quantity of the non-bound, “free” astringent stimulus in the saliva liquid might be more closely related to the sensory perception of astringency than the amount complexed or precipitated by proteins. It is therefore questionable as to whether oral perception of astringency is related to the complexation and/or precipitation of salivary proteins.