Causal modeling and inference for electricity markets

How does dynamic price information flow among Northern European electricity spot prices and prices of major electricity generation fuel sources? We use time series models combined with new advances in causal inference to answer these questions. Applying our methods to weekly Nordic and German electricity prices, and oil, gas and coal prices, with German wind power and Nordic water reservoir levels as exogenous variables, we estimate a causal model for the price dynamics, both for contemporaneous and lagged relationships. In contemporaneous time, Nordic and German electricity prices are interlinked through gas prices. In the long run, electricity prices and British gas prices adjust themselves to establish the equilibrium price level, since oil, coal, continental gas and EUR/USD are found to be weakly exogenous.     

Probability models of microcell coverage

Once a subscriber unit served by a microcell initiates a call, it must remain in the coverage area of the microcell long enough to complete call set up and hand-off functions. This restricts the minimum size attainable by a microcell. This paper derives the relationship between the microcell size, the call processing time, and the probability that a subscriber unit, initiating a call, will remain inside the microcell coverage area for at least the duration of call processing. Under simple assumptions, time spent in the coverage area of the microcellbefore andafter call initiation have the same cumulative density function, which is derived in this paper for traffic conditions encountered in highway and metropolitan settings.This paper is based on a contribution to the ETSI GSM2 Standards, Ronneby, Sweden, September 1991 [1].     

Design of an ohmic reactor to study the kinetics of thermal reactions in liquid products

An ohmic reactor was developed at a laboratory-scale to study the kinetics of thermal reactions in liquid products such as milk and infant formula in the UHT domain. Temperature mapping revealed good thermal homogeneity with a maximum difference of 3 °C in the treatment cell. The ohmic reactor enabled determination of the electrical conductivity of the product under the real thermal conditions with a precision of ±15%. Reproducible thermal profiles were obtained with a 2.3% relative variation for the heating phase, 1% for holding and 20% for cooling. The FAST index, giving a global measurement of the extent of the Maillard reaction in dairy products, was used to estimate the reproducibility of a thermal reaction with an average standard deviation of 3.8%. Finally, a semi-empirical model was developed to predict product temperature history during a complete thermal treatment with good adjustment for heating and holding and acceptable adjustment for cooling.     

Dietary patterns of adults living in Ouagadougou and their association with overweight

Background  

Urbanization in developing countries comes along with changes in food habits and living conditions and with an increase in overweight and associated health risks. The objective of the study was to describe dietary patterns of adults in Ouagadougou and to study their relationship with anthropometric status of the subjects.     

Robustness in Regulatory Interaction Networks. A Generic Approach with Applications at Different Levels: Physiologic, Metabolic and Genetic

Regulatory interaction networks are often studied on their dynamical side (existence of attractors, study of their stability). We focus here also on their robustness, that is their ability to offer the same spatiotemporal patterns and to resist to external perturbations such as losses of nodes or edges in the networks interactions architecture, changes in their environmental boundary conditions as well as changes in the update schedule (or updating mode) of the states of their elements (e.g., if these elements are genes, their synchronous coexpression mode versus their sequential expression). We define the generic notions of boundary, core, and critical vertex or edge of the underlying interaction graph of the regulatory network, whose disappearance causes dramatic changes in the number and nature of attractors (e.g., passage from a bistable behaviour to a unique periodic regime) or in the range of their basins of stability. The dynamic transition of states will be presented in the framework of threshold Boolean automata rules. A panorama of applications at different levels will be given: brain and plant morphogenesis, bulbar cardio-respiratory regulation, glycolytic/oxidative metabolic coupling, and eventually cell cycle and feather morphogenesis genetic control.