1,120 research outputs found

    One Step Forward, Two Steps Back: The Recognized But Undefined Federal Psychotherapist-Patient Privilege

    Get PDF
    Instead of demanding every man\u27s evidence, as is the general presumption, courts recognize the need for some evidence to remain private. Federal Rule of Evidence 501 governs federal evidentiary privileges without defining or identifying specific privileges. As a result, courts have developed privileges on a case-by-case basis, including the recognition of a psychotherapist-patient privilege. As different circuits pass judgment on the psychotherapist-patient privilege, conflict inevitably arises. Some circuits simply reject the privilege, while others recognize the privilege but apply it differently. The recognition of the psychotherapist-patient privilege was the necessary first step, but leaving the privilege undefined encourages litigation and undermines the privilege by making its application uncertain

    Nanosecond electro-optical switching with a repetition rate above 20MHz

    Full text link
    We describe an electro-optical switch based on a commercial electro-optic modulator (modified for high-speed operation) and a 340V pulser having a rise time of 2.2ns (at 250V). It can produce arbitrary pulse patterns with an average repetition rate beyond 20MHz. It uses a grounded-grid triode driven by transmitting power transistors. We discuss variations that enable analog operation, use the step-recovery effect in bipolar transistors, or offer other combinations of output voltage, size, and cost.Comment: 3 pages, 3 figures. Minor change

    A Hierarchial Neural Network Implementation for Forecasting

    Get PDF
    In this paper, a hierarchical neural network architecture for forecasting time series is presented. The architecture is composed of two hierarchical levels using a maximum likelihood competitive learning algorithm. The first level of the system has three experts each using backpropagation and a gating network to partition the input space in order to map the input vectors to the output vectors. The second level of the hierarchical network has an expert using fuzzy ART for producing the correct trend coming from the first level. The experiments show that the resulting network is capable of forecasting the changes in the input and identifying the trends correctl

    Algorithmic aspects of disjunctive domination in graphs

    Full text link
    For a graph G=(V,E)G=(V,E), a set DVD\subseteq V is called a \emph{disjunctive dominating set} of GG if for every vertex vVDv\in V\setminus D, vv is either adjacent to a vertex of DD or has at least two vertices in DD at distance 22 from it. The cardinality of a minimum disjunctive dominating set of GG is called the \emph{disjunctive domination number} of graph GG, and is denoted by γ2d(G)\gamma_{2}^{d}(G). The \textsc{Minimum Disjunctive Domination Problem} (MDDP) is to find a disjunctive dominating set of cardinality γ2d(G)\gamma_{2}^{d}(G). Given a positive integer kk and a graph GG, the \textsc{Disjunctive Domination Decision Problem} (DDDP) is to decide whether GG has a disjunctive dominating set of cardinality at most kk. In this article, we first propose a linear time algorithm for MDDP in proper interval graphs. Next we tighten the NP-completeness of DDDP by showing that it remains NP-complete even in chordal graphs. We also propose a (ln(Δ2+Δ+2)+1)(\ln(\Delta^{2}+\Delta+2)+1)-approximation algorithm for MDDP in general graphs and prove that MDDP can not be approximated within (1ϵ)ln(V)(1-\epsilon) \ln(|V|) for any ϵ>0\epsilon>0 unless NP \subseteq DTIME(VO(loglogV))(|V|^{O(\log \log |V|)}). Finally, we show that MDDP is APX-complete for bipartite graphs with maximum degree 33

    Reducing Occupational Distress in Veterinary Medicine Personnel with Acceptance and Commitment Training: A Pilot Study

    Get PDF
    Aims To determine whether an educational programme targeting the reaction of veterinary personnel to difficult client interactions reduced burden transfer, stress and burnout in veterinary staff. Methods Employees of three small-animal veterinary hospitals in the south-western United States of America were recruited and randomised to intervention (educational programme; n = 16) or control (no intervention; n = 18) groups. Participants of this randomised, parallel arms trial completed pre-programme assessment including the Burden Transfer Inventory (BTI), Perceived Stress Scale, and Copenhagen Burnout Inventory. Assessment was followed by two, group-format educational sessions, based on acceptance and commitment training, tailored to reducing reactivity to difficult veterinary client interactions (intervention group only). After training was completed, both groups were assessed using the same measures and the intervention participants provided use and acceptability ratings. Results Intervention participants rated the programme as useful and appropriate, and reported that programme techniques were used a median of 43 (min 9, max 68) times during the 2 weeks prior to retesting. Relative to pre-programme scores, median post-programme scores for reaction (subscore of BTI) to difficult client interactions decreased in the intervention group (33 vs. 54; p = 0.047), but not in the control group (51 vs. 59; p = 0.210). Changes in median scores for stress and burnout from pre- to post-programme were non-significant for both groups. Conclusions This pilot and feasibility trial showed high rates of acceptability and use by participants, as well as promising reductions in burden transfer. A larger scale clinical trial with follow-up at extended time points is needed to more fully examine the efficacy of this novel programme

    Smoothed Analysis of the Minimum-Mean Cycle Canceling Algorithm and the Network Simplex Algorithm

    Get PDF
    The minimum-cost flow (MCF) problem is a fundamental optimization problem with many applications and seems to be well understood. Over the last half century many algorithms have been developed to solve the MCF problem and these algorithms have varying worst-case bounds on their running time. However, these worst-case bounds are not always a good indication of the algorithms' performance in practice. The Network Simplex (NS) algorithm needs an exponential number of iterations for some instances, but it is considered the best algorithm in practice and performs best in experimental studies. On the other hand, the Minimum-Mean Cycle Canceling (MMCC) algorithm is strongly polynomial, but performs badly in experimental studies. To explain these differences in performance in practice we apply the framework of smoothed analysis. We show an upper bound of O(mn2log(n)log(ϕ))O(mn^2\log(n)\log(\phi)) for the number of iterations of the MMCC algorithm. Here nn is the number of nodes, mm is the number of edges, and ϕ\phi is a parameter limiting the degree to which the edge costs are perturbed. We also show a lower bound of Ω(mlog(ϕ))\Omega(m\log(\phi)) for the number of iterations of the MMCC algorithm, which can be strengthened to Ω(mn)\Omega(mn) when ϕ=Θ(n2)\phi=\Theta(n^2). For the number of iterations of the NS algorithm we show a smoothed lower bound of Ω(mmin{n,ϕ}ϕ)\Omega(m \cdot \min \{ n, \phi \} \cdot \phi).Comment: Extended abstract to appear in the proceedings of COCOON 201

    Minimal Obstructions for Partial Representations of Interval Graphs

    Full text link
    Interval graphs are intersection graphs of closed intervals. A generalization of recognition called partial representation extension was introduced recently. The input gives an interval graph with a partial representation specifying some pre-drawn intervals. We ask whether the remaining intervals can be added to create an extending representation. Two linear-time algorithms are known for solving this problem. In this paper, we characterize the minimal obstructions which make partial representations non-extendible. This generalizes Lekkerkerker and Boland's characterization of the minimal forbidden induced subgraphs of interval graphs. Each minimal obstruction consists of a forbidden induced subgraph together with at most four pre-drawn intervals. A Helly-type result follows: A partial representation is extendible if and only if every quadruple of pre-drawn intervals is extendible by itself. Our characterization leads to a linear-time certifying algorithm for partial representation extension

    On strongly chordal graphs that are not leaf powers

    Full text link
    A common task in phylogenetics is to find an evolutionary tree representing proximity relationships between species. This motivates the notion of leaf powers: a graph G = (V, E) is a leaf power if there exist a tree T on leafset V and a threshold k such that uv is an edge if and only if the distance between u and v in T is at most k. Characterizing leaf powers is a challenging open problem, along with determining the complexity of their recognition. This is in part due to the fact that few graphs are known to not be leaf powers, as such graphs are difficult to construct. Recently, Nevries and Rosenke asked if leaf powers could be characterized by strong chordality and a finite set of forbidden subgraphs. In this paper, we provide a negative answer to this question, by exhibiting an infinite family \G of (minimal) strongly chordal graphs that are not leaf powers. During the process, we establish a connection between leaf powers, alternating cycles and quartet compatibility. We also show that deciding if a chordal graph is \G-free is NP-complete, which may provide insight on the complexity of the leaf power recognition problem

    Partitioning SKA Dataflows for Optimal Graph Execution

    Full text link
    Optimizing data-intensive workflow execution is essential to many modern scientific projects such as the Square Kilometre Array (SKA), which will be the largest radio telescope in the world, collecting terabytes of data per second for the next few decades. At the core of the SKA Science Data Processor is the graph execution engine, scheduling tens of thousands of algorithmic components to ingest and transform millions of parallel data chunks in order to solve a series of large-scale inverse problems within the power budget. To tackle this challenge, we have developed the Data Activated Liu Graph Engine (DALiuGE) to manage data processing pipelines for several SKA pathfinder projects. In this paper, we discuss the DALiuGE graph scheduling sub-system. By extending previous studies on graph scheduling and partitioning, we lay the foundation on which we can develop polynomial time optimization methods that minimize both workflow execution time and resource footprint while satisfying resource constraints imposed by individual algorithms. We show preliminary results obtained from three radio astronomy data pipelines.Comment: Accepted in HPDC ScienceCloud 2018 Worksho

    Labels direct infants’ attention to commonalities during novel category learning

    Get PDF
    Recent studies have provided evidence that labeling can influence the outcome of infants’ visual categorization. However, what exactly happens during learning remains unclear. Using eye-tracking, we examined infants’ attention to object parts during learning. Our analysis of looking behaviors during learning provide insights going beyond merely observing the learning outcome. Both labeling and non-labeling phrases facilitated category formation in 12-month-olds but not 8-month-olds (Experiment 1). Non-linguistic sounds did not produce this effect (Experiment 2). Detailed analyses of infants’ looking patterns during learning revealed that only infants who heard labels exhibited a rapid focus on the object part successive exemplars had in common. Although other linguistic stimuli may also be beneficial for learning, it is therefore concluded that labels have a unique impact on categorization
    corecore