A comparative evaluation of interactive segmentation algorithms

In this paper we present a comparative evaluation of four popular interactive segmentation algorithms. The evaluation was carried out as a series of user-experiments, in which participants were tasked with extracting 100 objects from a common dataset: 25 with each algorithm, constrained within a time limit of 2 min for each object. To facilitate the experiments, a “scribble-driven” segmentation tool was developed to enable interactive image segmentation by simply marking areas of foreground and background with the mouse. As the participants refined and improved their respective segmentations, the corresponding updated segmentation mask was stored along with the elapsed time. We then collected and evaluated each recorded mask against a manually segmented ground truth, thus allowing us to gauge segmentation accuracy over time. Two benchmarks were used for the evaluation: the well-known Jaccard index for measuring object accuracy, and a new fuzzy metric, proposed in this paper, designed for measuring boundary accuracy. Analysis of the experimental results demonstrates the effectiveness of the suggested measures and provides valuable insights into the performance and characteristics of the evaluated algorithms.     

Unscented Kalman filter based nonlinear model predictive control of a LDPE autoclave reactor

This paper presents a multivariable nonlinear model predictive control (NMPC) scheme for the regulation of a low-density polyethylene (LDPE) autoclave reactor. A detailed mechanistic process model developed previously was used to describe the dynamics of the LDPE reactor and the properties of the polymer product. Closed-loop simulations are used to demonstrate the disturbance rejection and tracking performance of the NMPC algorithm for control of reactor temperature and weight-averaged molecular weight (WAMW). In addition, the effect of parametric uncertainty in the kinetic rate constants of the LDPE reactor model on closed-loop performance is discussed. The unscented Kalman filtering (UKF) algorithm is employed to estimate plant states and disturbances. All control simulations were performed under conditions of noisy process measurements and structural plant–model mismatch. Where appropriate, the performance of the NMPC algorithm is contrasted with that of linear model predictive control (LMPC). It is shown that for this application the closed-loop performance of the UKF based NMPC scheme is very good and is superior to that of the linear predictive controller.     

Fast computation of minimal elementary decompositions of metabolic flux vectors

The concept of elementary flux vector is valuable in a number of applications of metabolic engineering. For instance, in metabolic flux analysis, each admissible flux vector can be expressed as a non-negative linear combination of a small number of elementary flux vectors. However a critical issue concerns the total number of elementary flux vectors which may be huge because it combinatorially increases with the size of the metabolic network. In this paper we present a fast algorithm that randomly computes a decomposition of admissible flux vectors in a minimal number of elementary flux vectors without explicitly enumerating all of them.     

CMDB：成为单一来源的真相

配置管理数据库（CMDB）须能达成如下目标;例如：优化问题,制定IT流程,确定每个工作人员的数据分配。     

Experimenting with Isabelle in ZF set theory

The theorem prover Isabelle has been used to axiomatise ZF set theory with natural deduction and to prove a number of theorems concerning functions. In particular, the well-founded recursion theorem has been derived, allowing the definition of functions over recursive types (such as the length and the append functions for lists). The theory of functions has been developed sufficiently within ZF to include PP, the theory of continuous functions forming the basis of LCF. Most of the theorems have been derived using backward proofs, with a small amount of automation.The work has been carried out at the Computer Laboratory of the University of Cambridge.     

Distribution of the Amphipod Diporeia in Lake Superior: The Ring of Fire

Diporeia, formerly the dominant benthic macroinvertebrate in the Great Lakes, remains a keystone species in Lake Superior. Little is known, however, about fine scale amphipod distributions, especially as influenced by the production, transport and transformation of energy resources. Here, we document the distribution and abundance of Diporeia along 19 transects around the lake's perimeter. Regions of elevated density, averaging 958 ± 408 Diporeia/m² (mean ± S.D.) were observed along all transects, typically within slope habitat (depth of 30–125 m). Waters shoreward (shelf habitat, < 30 m) and lakeward (profundal habitat, > 125 m) of these regions supported significantly lower densities, averaging 239 ± 178/m² and 106 ± 59/m², respectively. Amphipods within regions of elevated density, termed here the Ring of Fire, account for two-thirds of the lakewide population while occupying only one-quarter of the benthic habitat. The Ring of Fire, observed lakewide as a band averaging 14.2 ± 9.4 km in width, is characterized as a region of transitional sediment deposition with gentle slope, proximate to nearshore locations of elevated primary production. Within the Ring of Fire exceptionally high densities are found in the south central region, where the Keweenaw Current and slope bathymetries serve to funnel production from adjoining regions of high production. Density measurements for the 173 stations sampled here are used to estimate lakewide Diporeia standing stock (22.5–37.7 trillion individuals, 4.4–7.4 Gg dry weight, 2.1–3.5 Gg C), individual and biomass density (274–460/m², 0.05–0.09 g DW/m², 0.03–0.04 gC/m²) and areal (0.02–0.03 g C/m²/yr) and total (1.6–2.6 Gg C/yr) production.     

Locally Limited and Fully Conserved RKDG2 Shallow Water Solutions with Wetting and Drying

This work extends a well-balanced second-order Runge-Kutta discontinuous Galerkin (RKDG2) scheme to provide conservative simulations for shallow flows involving wetting and drying over irregular topographies with friction effects. For this purpose, a wetting and drying technique designed originally for a finite volume (FV) scheme is improved and implemented, which includes the discretization of friction source terms via a splitting implicit integration approach. Another focus of this work is to design a fully conserved RKDG2 scheme to provide conservative solutions for both mass and momentum through a local slope limiting process. Several steady and transient benchmark tests with/without friction effects are simulated to validate the new solver and demonstrate the effects of different slope limiting processes, i.e. globally and locally slope limiting processes.     

EFFECT OF A PROPELLER AND GAS DIFFUSION ON BUBBLE NUCLEI DISTRIBUTION IN A LIQUID

A multi-bubble dynamics code accounting for gas diffusion in the liquid and through the bubble wall was developed and used to study the modification of a bubble nuclei population dynamics by a propeller.The propeller flow field was obtained using a Reynolds-Averaged Navier-Stokes(RANS) solver and bubble nuclei populations were propagated in this field.The numerical pro-cedure enabled establishment of the possibility of production behind the propeller of relatively large visible bubbles starting from typical ocean nuclei size distributions.The resulting larger bubbles are seen to cluster in the blade wakes and tip vortices.Parametric investigations of the initial nuclei size distribution,the dissolved gas concentration,and the cavitation number were conducted to ide-ntify their effects on bubble entrainment and the resultant void fractions and bubble distribution modifications downstream from the propeller.Imposed synthetic turbulence-like fluctuations unto the average RANS flow field were also used to study the effect avera-ging in the RANS procedure has on the results.     

Lyapunov exponential stability of 1-D linear hyperbolic systems of balance laws

Explicit boundary dissipative conditions are given for the exponential stability in $L^2$-norm of one-dimensional linear hyperbolic systems of balance laws ${?}_t\xi +\Lambda {?}_x\xi ?M\xi =0$ over a finite interval, when the matrix $M$ is marginally diagonally stable. The result is illustrated with an application to boundary feedback stabilisation of open channels represented by linearised Saint–Venant–Exner equations.     

Olfactory Responses to Aphid and Host Plant Volatile Releases: (E)-β-Farnesene an Effective Kairomone for the Predator Adalia bipunctata

The volatiles released from several aphid and host plant species, alone or associated, were studied for their infochemical role in prey location. Using a four-arm olfactometer, the attraction of several combinations of three aphid (Myzus persicae, Acyrthosiphon pisum, and Brevicoryne brassicae) and three plant (Vicia faba, Brassica napus, and Sinapis alba) species toward Adalia bipunctata larvae and adults was observed. Both predatory larvae and adults were attracted only by A. pisum and M. persicae when they were crushed, whatever the host plant. (E)-beta-farnesene, the aphid alarm pheromone, was the effective kairomone for the ladybird. Plant leaves alone (V. faba, B. napus, and S. alba) or in association with nonstressed whole aphids (the three species) did not have any attraction for the predator. The B. brassicae specialist aphid is the only prey that was not attracted to A. bipunctata larvae and adults, even if they were crushed. Release of B. brassicae molecules similar to the host plant allelochemicals was demonstrated by GC-MS analysis. The lack of behavioral response of the ladybird at short distance toward the cruciferous specialist aphid was related only to the absence of (E)-beta-farnesene in the aphid prey volatile pattern.