Theoretical foundations and implementation of business process diagrams’ complexity management technique based on highlights

Software and Systems Modeling - The main purpose of business process diagrams is to make the communication between process-related stakeholders more effective. To this end, they need to be simple...     

On the Derivative of Drawdown for Single Well Pumping Tests

The communication explains the physical meaning of the derivative of drawdown for a pumping test.     

SEQUIN: a grammar inference framework for analyzing malicious system behavior

Targeted attacks on IT systems are a rising threat to the confidentiality of sensitive data and the availability of critical systems. The emergence of Advanced Persistent Threats (APTs) made it paramount to fully understand the particulars of such attacks in order to improve or devise effective defense mechanisms. Grammar inference paired with visual analytics (VA) techniques offers a powerful foundation for the automated extraction of behavioral patterns from sequential event traces. To facilitate the interpretation and analysis of APTs, we present SEQUIN, a grammar inference system based on the Sequitur compression algorithm that constructs a context-free grammar (CFG) from string-based input data. In addition to recursive rule extraction, we expanded the procedure through automated assessment routines capable of dealing with multiple input sources and types. This automated assessment enables the accurate identification of interesting frequent or anomalous patterns in sequential corpora of arbitrary quantity and origin. On the formal side, we extended the CFG with attributes that help describe the extracted (malicious) actions. Discovery-focused pattern visualization of the output is provided by our dedicated KAMAS VA prototype.     

Tetranuclear Thioureacopper(II) Complexes

By replacement of methanol in the Cu₄OX₆(MeOH)₄ (X  Cl, Br) complexes with thiourea (tu), N,N′-diphenylthiourea (diftu), N,N′-dimethlthiourea (dimtu), tetramethylthiourea (tmtu) and acetylthiourea (actu), the complexes Cu₄OCl₆L₄ where L  tu, tu(0.3 Et₂O), diftu, dimtu, tmtu, actu (0.5Et₂O) and the complexes Cu₄OBr₆L₄, where L  tu, diftu, dimtu, tmtu have been prepared. Their infrared and electronic spectra indicate the presence of Cu₄O grouping and the trigonal bipyramidal coordination of copper(II). These complexes exhibit e.p.r. signals in the temperature range 100–260 K, in contrast to other known complexes of this structural type, which showed the e.p.r. signals at significantly lower temperatures. Thiourea and its derivatives are not able to reduce copper(II) in reaction with the tetranuclear Cu₄OX₆(MeOH)₄ complexes in methanol-ether solution due to the redox stabilizing effect of the tetranuclear structure.