TRAC

Abstract: Urban trac gathers increasing interest as cities become bigger, crowded and \smart". We present a system for heterogeneous stream processing and crowdsourcing supporting intelligent urban trac management. Complex events related to trac congestion (trends) are detected from heterogeneous sources involving xed sensors mounted on intersections and mobile sensors mounted on public transport vehicles. To deal with data veracity, a crowdsourcing component handles and resolves sensor disagreement. Furthermore, to deal with data sparsity, a trac modelling component oers information in areas with low sensor coverage. We demonstrate the system with a real-world use-case from Dublin city, Ireland.

Abstract: A plant canopy gap-size analyzer, the Tracing Radiation and Architecture of Canopies (TRAC), developed by Chen and Cihlar [Appl Opt. 34, 6211(1995)] and commercialized and by 3rd Wave Engineering (Nepean, Canada), has been used around the world to quantify the fraction of photosynthetically activeradiation absorbed by plant canopies, the leaf area index (LAI), and canopy architectural parameters. The TRAC is walked under a canopy along transects to measure sunflecks that are converted into a gap-size distribution. A numerical gap-removal technique is performed to remove gaps that are not theoretically possible in a random canopy. The resulting reduced gap-size distribution is used to quantify the heterogeneity of the canopy and to improve LAI measurements. It is explicitly shown here that the original derivation of the clumping index was missing a normalization factor. For a very clumped canopy with a large gap faction, the resulting LAI can be more than 100% smaller than previously estimated. A test case is used to demonstrate that the new clumping index derivation allows a more accurate change of LAI to be measured.

Abstract: The Siemens S7 protocol is commonly used in SCADA systems for communications between a Human Machine Interface (HMI) and the Programmable Logic Controllers (PLCs) This paper presents a model-based Intrusion Detection Systems (IDS) designed for S7 networks The approach is based on the key observation that S7 trac to and from a specic PLC is highly periodic; as a result, each HMI-PLC channel can be modeled using its own unique Deterministic Finite Automaton (DFA) The resulting DFA-based IDS is very sensitive and is able to ag anomalies such as a message appearing out of its position in the normal sequence or a message referring to a single unexpected bit The intrusion detection approach was evaluated on trac from two production systems Despite its high sensitivity, the system had a very low false positive rate - over 9982% of the trac was identied as normal

Abstract: The Los Alamos National Laboratory is developing the Transient Reactor Analysis Code (TRAC) to provide advanced best-estimate predictions of postulated accidents in light-water reactors. The TRAC-PF1/MOD1 program provides this capability for pressurized water reactors and for many thermal-hydraulic test facilities. The code features either a one- or a three-dimensional treatment of the pressure vessel and its associated internals, a two-fluid nonequilibrium hydrodynamics model with a noncondensable gas field and solute tracking, flow-regime-dependent constitutive equation treatment, optional reflood tracking capability for bottom-flood and falling-film quench fronts, and consistent treatment of entire accident sequences including the generation of consistent initial conditions. The stability-enhancing two-step (SETS) numerical algorithm is used in the one-dimensional hydrodynamics and permits this portion of the fluid dynamics to violate the material Courant condition. This technique permits large time steps and, hence, reduced running time for slow transients.