Estimation of linear trend onset in time series

We propose a method to detect the onset of linear trend in a time series and estimate the change point T from the profile of a linear trend test statistic, computed on consecutive overlapping time windows along the time series. We compare our method to two standard methods for trend change detection and evaluate them with Monte Carlo simulations for different time series lengths, autocorrelation strengths, trend slopes and distribution of residuals. The proposed method turns out to estimate T better for small and correlated time series. The methods were also applied to global temperature records suggesting different turning points.     

Molecular dynamics at the receptor level of immunodominant myelin basic protein epitope 87-99 implicated in multiple sclerosis and its antagonists altered peptide ligands: triggering of immune response

This work reports molecular dynamics studies at the receptor level of the immunodominant myelin basic protein (MBP) epitope 87-99 implicated in multiple sclerosis, and its antagonists altered peptide ligands (APLs), namely [Arg91, Ala96] MBP87-99 and [Ala91,96] MBP87-99. The interaction of each peptide ligand with the receptor human leukocyte antigen HLA-DR2b was studied, starting from X-ray structure with pdb code: 1ymm. This is the first such study of APL-HLA-DR2b complexes, and hence the first attempt to gain a better understanding of the molecular recognition mechanisms that underlie TCR antagonism by these APLs. The amino acids His88 and Phe89 serve as T-cell receptor (TCR) anchors in the formation of the trimolecular complex TCR-peptide-HLA-DR2b, where the TCR binds in a diagonal, off-centered mode to the peptide-HLA complex. The present findings indicate that these two amino acids have a different orientation in the APLs [Arg91, Ala96] MBP87-99 and [Ala91,96] MBP87-99: His88 and Phe89 remain buried in HLA grooves and are not available for interaction with the TCR. We propose that this different topology could provide a possible mechanism of action for TCR antagonism.     

Palaeoenvironmental Conditions of the Mavropigi Lignites,Ptolemais Basin,Greece: A Petrological Study

The aim of this study is to interpret the palaeoenvironmental conditions established during the formation of several lignite seams at the Mavropigi deposit, Ptolemais, Greece (corehole MAK-48). In nine representative lignite samples, ash contents, as well as the contents of the elements C, H, N, O, and S were determined. Polished block sections from the same samples were examined under the microscope. The ash contents (750°C) of the studied lignite seams range between 10–29% (on dry basis). The contents of C, H, N, and O display values between 36–55%, 2.4–4.6%, 0.7–2%, and 21–37.5%, respectively, while S contents do not exceed 1.4%. Huminite is the prevailing maceral group (87–95%). All the samples, except No. 35, display a distinct prevalence in detrohuminite maceral subgroup (up to 69 vol%, mmf). Liptinite and inertinite maceral groups show low contents, which do not exceed 9% and 7%, respectively. The Mavropigi lignites are medium to low grade coals and can be regarded as peat to lignite in terms of thermal maturity. The studied lignite seams formed in fens, possibly from herbaceous plants under limnotelmatic regime. During peat deposition, conditions were very moist and intense reducing with increased bacterial activity. The ratio of plant growth and peat accumulation versus rise of water table due to the subsidence rate was not well balanced. As a result, the petrographical composition of the Mavropigi lignites is related either to a long residence time of the organic matter in the acrotelm or to a herbaceous vegetation origin.     

Towards a flexible trust establishment framework for sensor networks

Wireless sensor networks highly depend on the distributed cooperation among network nodes. Trust establishment frameworks provide the means for representing, evaluating, maintaining and distributing trust within the network, and serve as the basis for higher level security services. In this paper, we propose a trust establishment framework targeted sensor networks that can uniformly support the needs of nodes with highly diverse network roles and capabilities, by exploiting the pre-deployment knowledge on the network topology and the information flows. The framework allows for flexibility by combining aspects from alternative approaches on trust establishment on common evaluation metrics, and enables controlled trust evolution based on the network pre-configuration.     

Specifying and verifying usage control models and policies in TLA $$^+$$ +

International Journal on Software Tools for Technology Transfer - Novel computing paradigms, e.g., the Cloud, introduce new requirements with regard to access control such as utilization of...     

Formal methods and tools for industrial critical systems

International Journal on Software Tools for Technology Transfer - Formal methods and tools have become well established and widely applied to ensure the correctness of fundamental components of...     

Petrographic Characteristics of the Kardia Lignites (Core KT6A-3), Ptolemais Basin (Greece)

The aim of this study is to provide useful coal-petrographic data, which will further help the characterization, exploitation, and utilization of the Kardia lignite deposit and also initially to access the depositional conditions mainly in terms of water table level and subsidence rate of the fen substrate. Ash contents, as well as the C, H, N, O, and S were determined in nine lignite samples from core KT6A-3. The ash contents (750°C) of the studied lignite seams range among 14–37% (on dry basis). Contents of C, H, N, and O have values between 34–52%, 2.5–4.2%, 0.8–2%, and 21–30.6%, respectively. Sulfur does not exceed 1.2%. Huminite group dominates with values between 84–99 vol%, mmf. All samples display a distinct prevalence in detrohuminite (up to 82 vol%) with attrinite being most abundant. Liptinite and inertinite macerals have low contents, which do not exceed 8% and 12%, respectively. The Kardia lignites are medium to very low-grade coals. They formed in fens under limnotelmatic regime and originated from herbaceous vegetation. During peat deposition, conditions were well moist, intense reducing, and favored increased bacterial activity. The ratio of plant growth and peat accumulation versus rise of water table due to the subsidence rate was not well balanced. The petrographical composition of the Kardia lignites is related either to a long residence time of the organic matter in the acrotelm or to an herbaceous vegetation origin.     

Comparative design study of a diesel exhaust gas heat exchanger for truck applications with conventional and state of the art heat transfer enhancements

The exhaust gas of heavy duty diesel engines can provide an important heat source that may be used in a number of ways to provide additional power and improve overall engine efficiency. The sizing of a heat exchanger that can manage the heat load and still be of reasonable size and weight without excessive pressure drop is of significant importance especially for truck applications. This is the subject of the present work. To approach the problem, a total of five different configurations are investigated and a comparison of conventional and state of the art heat transfer enhancement technologies is included. Two groups of configurations are examined: (a) a classical shell and tube heat exchanger using staggered cross-flow tube bundles with smooth circular tubes, finned tubes and tubes with dimpled surfaces and (b) a cross-flow plate heat exchanger, initially with finned surfaces on the exhaust gas side and then with 10 ppi and 40 ppi metal foam material substituting for the fins. Calculations were performed, using established heat exchanger design methodologies and recently published data from the literature to size the aforementioned configurations. The solutions provided reduce the overall heat exchanger size, with the plate and fin type consisting of plain fins presenting the minimum pressure drop (up to 98% reduction compared to the other configurations), and the 40 ppi metal foam being the most compact in terms of size and weight. Durability of the solutions is another issue which will be examined in a future investigation. However, coupling of the exhaust heat exchanger after a particulate trap appears to be the most promising solution to avoid clogging from soot accumulation.