49,936 research outputs found

    Outlier Detection from Network Data with Subnetwork Interpretation

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    Detecting a small number of outliers from a set of data observations is always challenging. This problem is more difficult in the setting of multiple network samples, where computing the anomalous degree of a network sample is generally not sufficient. In fact, explaining why the network is exceptional, expressed in the form of subnetwork, is also equally important. In this paper, we develop a novel algorithm to address these two key problems. We treat each network sample as a potential outlier and identify subnetworks that mostly discriminate it from nearby regular samples. The algorithm is developed in the framework of network regression combined with the constraints on both network topology and L1-norm shrinkage to perform subnetwork discovery. Our method thus goes beyond subspace/subgraph discovery and we show that it converges to a global optimum. Evaluation on various real-world network datasets demonstrates that our algorithm not only outperforms baselines in both network and high dimensional setting, but also discovers highly relevant and interpretable local subnetworks, further enhancing our understanding of anomalous networks

    Creativity and the Brain

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    Neurocognitive approach to higher cognitive functions that bridges the gap between psychological and neural level of description is introduced. Relevant facts about the brain, working memory and representation of symbols in the brain are summarized. Putative brain processes responsible for problem solving, intuition, skill learning and automatization are described. The role of non-dominant brain hemisphere in solving problems requiring insight is conjectured. Two factors seem to be essential for creativity: imagination constrained by experience, and filtering that selects most interesting solutions. Experiments with paired words association are analyzed in details and evidence for stochastic resonance effects is found. Brain activity in the process of invention of novel words is proposed as the simplest way to understand creativity using experimental and computational means. Perspectives on computational models of creativity are discussed

    Asymmetric Gepner Models II. Heterotic Weight Lifting

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    A systematic study of "lifted" Gepner models is presented. Lifted Gepner models are obtained from standard Gepner models by replacing one of the N=2 building blocks and the E8E_8 factor by a modular isomorphic N=0N=0 model on the bosonic side of the heterotic string. The main result is that after this change three family models occur abundantly, in sharp contrast to ordinary Gepner models. In particular, more than 250 new and unrelated moduli spaces of three family models are identified. We discuss the occurrence of fractionally charged particles in these spectra.Comment: 46 pages, 17 figure

    Renewing the framework for secondary mathematics : spring 2008 subject leader development meeting : sessions 2, 3 and 4

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    How Effective Are Police? The Problem of Clearance Rates and Criminal Accountability

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    In recent years, the national conversation in criminal justice has centered on police. Are police using excessive force? Should they be monitored more closely? Do technology and artificial intelligence improve policing? The implied core question across these national debates is whether police are effective at their jobs. Yet we have not explored how effective police are or determined how best to measure police effectiveness. This Article endeavors to measure how effective police are at their principal function—solving crime. The metric most commonly used to measure police effectiveness at crime-solving is a “clearance rate:” the proportion of reported crimes for which police arrest a person and refer them for prosecution. But clearance rates are inadequate for many reasons, including the fact that they are highly manipulable. This Article therefore provides a set of new metrics that have never been used systematically to study police effectiveness—referred to as “criminal accountability” metrics. Criminal Accountability examines the full course of a crime to determine whether crime that is committed is detected and ultimately resolved by police. Taking into account the prevalence and the number of crimes solved by police, the proportion of crimes solved in America is dramatically lower than we realize. Only with a clearer conversation, rooted in accurate data about the effectiveness of the American police system, can we attempt a path toward increased criminal accountability and public safety

    Management control of supplier relationships in manufacturing: a case study in the automotive industry.

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    This paper studies management control design of supplier relationships in manufacturing, a supply chain phase currently under-explored. Compared to supplier relations during procurement and R&D, which research found to be governed by a combination of formal and informal controls, supplier relations in manufacturing are more formal, so that they could be governed by more formal and less informal controls. To refine the management control system and influencing contingencies, we propose a theoretical framework specifically adapted for the manufacturing stage. This framework is investigated by an in depth case study of the supplier management control of a Volvo Cars production facility. We identify three types of suppliers visualizing the associations in the framework and illustrating the framework’s explicative power in (automotive) manufacturing. Furthermore, the case contradicts that supplier relations in the manufacturing phase are governed by little informal control, because the automaker highly values the role of trust building and social pressure. Most notably, a structured supplier team functions as a clan and establishes informal control among participating suppliers, which strengthens the automaker’s control on dyadic supplier relations.management control; supplier relationships; manufacturing; contingency theory; case research;

    The Structured Process Modeling Theory (SPMT): a cognitive view on why and how modelers benefit from structuring the process of process modeling

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    After observing various inexperienced modelers constructing a business process model based on the same textual case description, it was noted that great differences existed in the quality of the produced models. The impression arose that certain quality issues originated from cognitive failures during the modeling process. Therefore, we developed an explanatory theory that describes the cognitive mechanisms that affect effectiveness and efficiency of process model construction: the Structured Process Modeling Theory (SPMT). This theory states that modeling accuracy and speed are higher when the modeler adopts an (i) individually fitting (ii) structured (iii) serialized process modeling approach. The SPMT is evaluated against six theory quality criteria
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