Travel cost and time measurement in travel cost models.

Cost; Measurement; Model; Models; Time; Working;

Analysis of multi-stage open shop processing systems

We study algorithmic problems in multi-stage open shop processing systems that are centered around reachability and deadlock detection questions. We characterize safe and unsafe system states. We show that it is easy to recognize system states that can be reached from the initial state (where the system is empty), but that in general it is hard to decide whether one given system state is reachable from another given system state. We show that the problem of identifying reachable deadlock states is hard in general open shop systems, but is easy in the special case where no job needs processing on more than two machines (by linear programming and matching theory), and in the special case where all machines have capacity one (by graph-theoretic arguments).Comment: 19 pages, no figure

Realizing small tournaments through few permutations

Every tournament on 7 vertices is the majority relation of a 3-permutation profile, and there exist tournaments on 8 vertices that do not have this property. Furthermore every tournament on 8 or 9 vertices is the majority relation of a 5-permutation profile

Using a gamified monitoring app to change adolescents' snack intake : the development of the REWARD app and evaluation design

Background: As the snacking pattern of European adolescents is of great concern, effective interventions are necessary. Till now health promotion efforts in children and adolescents have had only limited success in changing adolescents' eating patterns and anthropometrics. Therefore, the present study proposes an innovative approach to influence dietary behaviors in youth based on new insights on effective behavior change strategies and attractive intervention channels to engage adolescents. This article describes the rationale, the development, and evaluation design of the 'Snack Track School' app. The aim of the app is to improve the snacking patterns of Flemish 14- to 16-year olds. Methods: The development of the app was informed by the systematic, stepwise, iterative, and collaborative principles of the Intervention Mapping protocol. A four week mHealth intervention was developed based on the dual-system model with behavioral change strategies targeting both the reflective (i.e., active learning, advance organizers, mere exposure, goal-setting, monitoring, and feedback) and automatic processes (i.e., rewards and positive reinforcement). This intervention will be evaluated via a controlled pre-post design in Flemish schools among 1400 adolescents. Discussion: When this intervention including strategies focused on both the reflective and automatic pathway proves to be effective, it will offer a new scientifically-based vision, guidelines and practical tools for public health and health promotion (i.e., incorporation of learning theories in intervention programs)

Birth weight and early lung compliance as predictors of short-term outcome in premature infants with respiratory distress syndrome

No Abstract

Quasihomomorphisms from the integers into Hamming metrics

A function f : Z → Qn is a c-quasihomomorphism if the Hamming distance between f(x + y) and f(x) + f(y) is at most c for all x, y ∈ Z. We show that any c-quasihomomorphism has distance at most some constant C(c) to an actual group homomorphism; here C(c) depends only on c and not on n or f. This gives a positive answer to a special case of a question posed by Kazhdan and Ziegler

A GIS-based hydrographic resurvey strategy of the Belgian Continental Shelf

Using a GIS-based approach, bathymetric surveys and maritime traffic records were combined to determine resurvey priorities within the Belgian Continental Shelf (BCS). Four reference layers were produced: (1) water depth; (2) maximum absolute change in water depth; (3) ship traffic intensity; (4) maximum ship draught. The reference layers were reclassified and merged into a weighted overlay analysis. Two combinations of layers and weight factors were used and resulted in priority maps differing greatly from each other. The reliability of the analysis depends on the way weight factors are assigned, and on the availability and accuracy of the data. These are limited for bathymetric surveys. This empirical GIS-based methodology can be applied as a whole to a zone showing various morphodynamic patterns. It can also be automated: additional datasets can be included in the analysis, and different scenarios and assumptions can be easily tested

Comparison of LFP-Based and Spike-Based Spectro-Temporal Receptive Fields and Cross-Correlation in Cat Primary Auditory Cortex

Multi-electrode array recordings of spike and local field potential (LFP) activity were made from primary auditory cortex of 12 normal hearing, ketamine-anesthetized cats. We evaluated 259 spectro-temporal receptive fields (STRFs) and 492 frequency-tuning curves (FTCs) based on LFPs and spikes simultaneously recorded on the same electrode. We compared their characteristic frequency (CF) gradients and their cross-correlation distances. The CF gradient for spike-based FTCs was about twice that for 2–40 Hz-filtered LFP-based FTCs, indicating greatly reduced frequency selectivity for LFPs. We also present comparisons for LFPs band-pass filtered between 4–8 Hz, 8–16 Hz and 16–40 Hz, with spike-based STRFs, on the basis of their marginal frequency distributions. We find on average a significantly larger correlation between the spike based marginal frequency distributions and those based on the 16–40 Hz filtered LFP, compared to those based on the 4–8 Hz, 8–16 Hz and 2–40 Hz filtered LFP. This suggests greater frequency specificity for the 16–40 Hz LFPs compared to those of lower frequency content. For spontaneous LFP and spike activity we evaluated 1373 pair correlations for pairs with >200 spikes in 900 s per electrode. Peak correlation-coefficient space constants were similar for the 2–40 Hz filtered LFP (5.5 mm) and the 16–40 Hz LFP (7.4 mm), whereas for spike-pair correlations it was about half that, at 3.2 mm. Comparing spike-pairs with 2–40 Hz (and 16–40 Hz) LFP-pair correlations showed that about 16% (9%) of the variance in the spike-pair correlations could be explained from LFP-pair correlations recorded on the same electrodes within the same electrode array. This larger correlation distance combined with the reduced CF gradient and much broader frequency selectivity suggests that LFPs are not a substitute for spike activity in primary auditory cortex