4,356 research outputs found
N-(5-Ethylsulfanyl-1,3,4-thiadiazol-2-yl)-2-(4,5,6,7-tetrahydrothieno[3,2-c]pyridin-5-yl)acetamide
In the title compound, C13H16N4OS3, a thienopyridinederivative, the tetrahydropyridine ring exhibits a half-chair conformation, and the folded conformation of the molecule is defined by the N—C—C—N torsion angle of −78.85 (16)°. The crystal packing features intermolecular C—H⋯N, N—H⋯N and C—H⋯O hydrogen bonds
N-(2-Chloropyrimidin-4-yl)-N,2-dimethyl-2H-indazol-6-amine
In the title compound, C13H12ClN5, which is a derivative of the antitumor agent pazopanib {systematic name: 5-[[4-[(2,3-dimethyl-2H-indazol-6-yl)methylamino]-2-pyrimidinyl]amino]-2-methylbenzolsulfonamide}, the indazole and pyrimidine fragments form a dihedral angle of 62.63 (5)°. In the crystal, pairs of molecules related by twofold rotational symmetry are linked into dimers through π–π interactions between the indazole ring systems [centroid–centroid distance = 3.720 (2) Å]. Weak intermolecular C—H⋯N hydrogen bonds further assemble these dimers into columns propagated in [001]
1-[4-(3-{[5-(4-Chlorophenyl)furan-2-yl]methylideneamino}-2,5-dioxoimidazolidin-1-yl)butyl]-4-methylpiperazine-1,4-diium dichloride hemihydrate
The title compound, C23H30ClN5O3
2+·2Cl−·0.5H2O, was synthesized by N-alkylation of 1-({[5-(4-chlorophenyl)-2-furanyl]methylene}amino)-2,4-imidazolidinedione with 1-bromo-4-chlorobutane, and N-methylpiperazine. In the crystal, the cations, anions and water molecules are linked by O—H⋯Cl and N—H⋯Cl hydrogen bonds
1-[4-(4-Nitrophenyl)piperazin-1-yl]-2-(4,5,6,7-tetrahydrothieno[3,2-c]pyridin-5-yl)ethanone
The title compound, C19H22N4O3S, comprises a thienopyridine moiety which is characteristic for antiplatelet agents of the clopidogrel class of compounds. In the crystal, inversion dimers are formed through pairs of C—H⋯O interactions. The benzene ring plane and the nitro plane are almost coplanar, with a dihedral angle of 0.83 (2)°. The piperazine ring adopts a chair conformation
Intensity-free Integral-based Learning of Marked Temporal Point Processes
In the marked temporal point processes (MTPP), a core problem is to
parameterize the conditional joint PDF (probability distribution function)
for inter-event time and mark , conditioned on the history.
The majority of existing studies predefine intensity functions. Their utility
is challenged by specifying the intensity function's proper form, which is
critical to balance expressiveness and processing efficiency. Recently, there
are studies moving away from predefining the intensity function -- one models
and separately, while the other focuses on temporal point
processes (TPPs), which do not consider marks. This study aims to develop
high-fidelity for discrete events where the event marks are either
categorical or numeric in a multi-dimensional continuous space. We propose a
solution framework IFIB (\underline{I}ntensity-\underline{f}ree
\underline{I}ntegral-\underline{b}ased process) that models conditional joint
PDF directly without intensity functions. It remarkably simplifies
the process to compel the essential mathematical restrictions. We show the
desired properties of IFIB and the superior experimental results of IFIB on
real-world and synthetic datasets. The code is available at
\url{https://github.com/StepinSilence/IFIB}
Explainable History Distillation by Marked Temporal Point Process
Explainability of machine learning models is mandatory when researchers
introduce these commonly believed black boxes to real-world tasks, especially
high-stakes ones. In this paper, we build a machine learning system to
automatically generate explanations of happened events from history by \gls{ca}
based on the \acrfull{tpp}. Specifically, we propose a new task called
\acrfull{ehd}. This task requires a model to distill as few events as possible
from observed history. The target is that the event distribution conditioned on
left events predicts the observed future noticeably worse. We then regard
distilled events as the explanation for the future. To efficiently solve
\acrshort{ehd}, we rewrite the task into a \gls{01ip} and directly estimate the
solution to the program by a model called \acrfull{model}. This work fills the
gap between our task and existing works, which only spot the difference between
factual and counterfactual worlds after applying a predefined modification to
the environment. Experiment results on Retweet and StackOverflow datasets prove
that \acrshort{model} significantly outperforms other \acrshort{ehd} baselines
and can reveal the rationale underpinning real-world processes
Bayesian Criterion for Re-randomization
Re-randomization has gained popularity as a tool for experiment-based causal
inference due to its superior covariate balance and statistical efficiency
compared to classic randomized experiments. However, the basic re-randomization
method, known as ReM, and many of its extensions have been deemed sub-optimal
as they fail to prioritize covariates that are more strongly associated with
potential outcomes. To address this limitation and design more efficient
re-randomization procedures, a more precise quantification of covariate
heterogeneity and its impact on the causal effect estimator is in a great
appeal. This work fills in this gap with a Bayesian criterion for
re-randomization and a series of novel re-randomization procedures derived
under such a criterion. Both theoretical analyses and numerical studies show
that the proposed re-randomization procedures under the Bayesian criterion
outperform existing ReM-based procedures significantly in effectively balancing
covariates and precisely estimating the unknown causal effect
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