On Formal Modeling and Validation of Wireless Sensor Network Protocols

Formal verification is becoming more and more important in the field of wireless networks (WSN). The general purpose formal method called Event-B is the latest incarnation of the B Method: it is a proof based approach with a formal notation and refinement technique for modeling and verifying systems. Refinement enables implementation level features to be proven correct with respect to an abstract specification of the system. This paper proposes an initial attempt to model and verify consistency and correctness of a WSN operation in its different layers. Several formal models are introduced for this type of networks. In the first time, coloured Petri net are used to elaborate network layer models, then each one will be detailed by an Event-B formalism, while proofs are carried out using the RODIN platform which is an integrated development framework for Event-B.

     

Crystallization of Enantiomerically Pure Proteins from Quasi‐Racemic Mixtures: Structure Determination by X‐Ray Diffraction of Isotope‐Labeled Ester Insulin and Human Insulin

As a part of a program aimed towards the study of the dynamics of human insulin‐protein dimer formation using two‐dimensional infrared spectroscopy, we used total chemical synthesis to prepare stable isotope labeled [(1‐¹³C=¹⁸O)Phe^B24)] human insulin, via [(1‐¹³C=¹⁸O)Phe^B24)] ester insulin as a key intermediate product that facilitates folding of the synthetic protein molecule (see preceding article). Here, we describe the crystal structure of the synthetic isotope‐labeled ester insulin intermediate and the product synthetic human insulin. Additionally, we present our observations on hexamer formation with these two proteins in the absence of phenol derivatives and/or Zn metal ions. We also describe and discuss the fractional crystallization of quasi‐racemic protein mixtures containing each of these two synthetic proteins.     

Recommended guidelines for optimal design of a plastic surgery service during mass casualty events

OBJECTIVE: The objectives of the study were to evaluate the pattern of plastic surgery (PS) team intervention during the first 12 hours after a mass casualty blast. METHODS: The records of 272 civilians injured from 1994 to 1997 in Tel Aviv were reviewed. Patients' injuries were classified according to the nature of their PS injury and the type of PS intervention. The procedure time and number of plastic surgeons involved were recorded in 20-minute intervals. The average and standard deviation of the peak demand (PD) timing for PS intervention were calculated. Linear correlation between the PD and the total number of wounded transferred to the Tel Aviv Sourasky Medical Center was evaluated by the correlation coefficient. RESULTS: A distinct "double-peak" and five phases pattern of PS team intervention were observed. A linear correlation and a 1:5 ratio were found between the total number of wounded transferred to the Tel Aviv Sourasky Medical Center and the PD for PS intervention. CONCLUSIONS: PS involvement has a predicted pattern related to the patient volume. Guidelines based on the conclusions drawn from this study can ensure an ordered, efficacious level of PS care during these events. A triple team plan is suggested, and adjustments in medical resources according to the specific nature of the event are described.