1,482 research outputs found
High spin baryon in hot strongly coupled plasma
We consider a strings-junction holographic model of probe baryon in the
finite-temperature supersymmetric Yang-Mills dual of the AdS-Schwarzschild
black hole background. In particular, we investigate the screening length for
high spin baryon composed of rotating N_c heavy quarks. To rotate quarks by
finite force, we put hard infrared cutoff in the bulk and give quarks finite
mass. We find that N_c microscopic strings are embedded reasonably in the bulk
geometry when they have finite angular velocity \omega, similar to the meson
case. By defining the screening length as the critical separation of quarks, we
compute the \omega dependence of the baryon screening length numerically and
obtain a reasonable result which shows that baryons with high spin dissociate
more easily. Finally, we discuss the relation between J and E^2 for baryons.Comment: 18 pages, 19 figures, version to appear in JHE
In the Absence of Authenticity: An Interpretation of Contemporary Chinese Architecture
Like human beings, architecture has to choose its way of existence: a personality true to one's own nature or the preconceived roles of an actor. From this Heideggerian view, the paper examines the formal characteristics of contemporary Chinese architecture. It also explores how social and cultural conditions and intellectuals' sense of responsibility have contributed to the current state of architecture in China
Q -permutable subgroups of finite groups
A subgroup H of a group G is called Q-permutable in G if there exists a subgroup B of G such that (1) G=HB and (2) if H1 is a maximal subgroup of H containing HQG, then H1B=BH1<G, where HQG is the largest permutable subgroup of G contained in H. In this paper we prove that: Let F be a saturated formation containing U and G be a group with a normal subgroup H such that G/H∈F. If every maximal subgroup of every noncyclic Sylow subgroup of F∗(H) having no supersolvable supplement in G is Q-permutable in G, then G∈F.Пiдгрупу H групи G називають Q-переставною в G, якщо iснує пiдгрупа B групи G така, що: 1) G=HB та 2) якщо H1 — максимальна пiдгрупа H, що мiстить HQG, то H1B=BH1<G, де HQG є найбiльшою переставною пiдгрупою G, що мiститься в H. У цiй роботi доведено наступне твердження. Нехай F — насичена формацiя, що мiстить U, а G — група з нормальною пiдгрупою H такою, що G/H∈F. Якщо кожна максимальна пiдгрупа кожної нециклiчної силовської пiдгрупи F∗(H), що не має надрозв’язного доповнення в G, є Q-переставною в G, то G∈F
DebCSE: Rethinking Unsupervised Contrastive Sentence Embedding Learning in the Debiasing Perspective
Several prior studies have suggested that word frequency biases can cause the
Bert model to learn indistinguishable sentence embeddings. Contrastive learning
schemes such as SimCSE and ConSERT have already been adopted successfully in
unsupervised sentence embedding to improve the quality of embeddings by
reducing this bias. However, these methods still introduce new biases such as
sentence length bias and false negative sample bias, that hinders model's
ability to learn more fine-grained semantics. In this paper, we reexamine the
challenges of contrastive sentence embedding learning from a debiasing
perspective and argue that effectively eliminating the influence of various
biases is crucial for learning high-quality sentence embeddings. We think all
those biases are introduced by simple rules for constructing training data in
contrastive learning and the key for contrastive learning sentence embedding is
to mimic the distribution of training data in supervised machine learning in
unsupervised way. We propose a novel contrastive framework for sentence
embedding, termed DebCSE, which can eliminate the impact of these biases by an
inverse propensity weighted sampling method to select high-quality positive and
negative pairs according to both the surface and semantic similarity between
sentences. Extensive experiments on semantic textual similarity (STS)
benchmarks reveal that DebCSE significantly outperforms the latest
state-of-the-art models with an average Spearman's correlation coefficient of
80.33% on BERTbase
On Reachability Analysis of Pushdown Systems with Transductions: Application to Boolean Programs with Call-by-Reference
Pushdown systems with transductions (TrPDSs) are an extension of pushdown systems (PDSs) by associating each transition rule with a transduction, which allows to inspect and modify the stack content at each step of a transition rule. It was shown by Uezato and Minamide that TrPDSs can model PDSs with checkpoint and discrete-timed PDSs. Moreover, TrPDSs can be simulated by PDSs and the predecessor configurations pre^*(C) of a regular set C of configurations can be computed by a saturation procedure when the closure of the transductions in TrPDSs is finite. In this work, we comprehensively investigate the reachability problem of finite TrPDSs. We propose a novel saturation procedure to compute pre^*(C) for finite TrPDSs. Also, we introduce a saturation procedure to compute the successor configurations post^*(C) of a regular set C of configurations for finite TrPDSs. From these two saturation procedures, we present two efficient implementation algorithms to compute pre^*(C) and post^*(C). Finally, we show how the presence of transductions enables the modeling of Boolean programs with call-by-reference parameter passing. The TrPDS model has finite closure of transductions which results in model-checking approach for Boolean programs with call-by-reference parameter passing against safety properties
SmartUnit: Empirical Evaluations for Automated Unit Testing of Embedded Software in Industry
In this paper, we aim at the automated unit coverage-based testing for
embedded software. To achieve the goal, by analyzing the industrial
requirements and our previous work on automated unit testing tool CAUT, we
rebuild a new tool, SmartUnit, to solve the engineering requirements that take
place in our partner companies. SmartUnit is a dynamic symbolic execution
implementation, which supports statement, branch, boundary value and MC/DC
coverage. SmartUnit has been used to test more than one million lines of code
in real projects. For confidentiality motives, we select three in-house real
projects for the empirical evaluations. We also carry out our evaluations on
two open source database projects, SQLite and PostgreSQL, to test the
scalability of our tool since the scale of the embedded software project is
mostly not large, 5K-50K lines of code on average. From our experimental
results, in general, more than 90% of functions in commercial embedded software
achieve 100% statement, branch, MC/DC coverage, more than 80% of functions in
SQLite achieve 100% MC/DC coverage, and more than 60% of functions in
PostgreSQL achieve 100% MC/DC coverage. Moreover, SmartUnit is able to find the
runtime exceptions at the unit testing level. We also have reported exceptions
like array index out of bounds and divided-by-zero in SQLite. Furthermore, we
analyze the reasons of low coverage in automated unit testing in our setting
and give a survey on the situation of manual unit testing with respect to
automated unit testing in industry.Comment: In Proceedings of 40th International Conference on Software
Engineering: Software Engineering in Practice Track, Gothenburg, Sweden, May
27-June 3, 2018 (ICSE-SEIP '18), 10 page
RIS-ADMM: A RIS and ADMM-Based Passive and Sparse Sensing Method With Interference Removal
Reconfigurable Intelligent Surfaces (RIS) emerge as promising technologies in
future radar and wireless communication domains. This letter addresses the
passive sensing issue utilizing wireless communication signals and RIS amidst
interference from wireless access points (APs). We introduce an atomic norm
minimization (ANM) approach to leverage spatial domain target sparsity and
estimate the direction of arrival (DOA). However, the conventional semidefinite
programming (SDP)-based solutions for the ANM problem are complex and lack
efficient realization. Consequently, we propose a RIS-ADMM method, an
innovative alternating direction method of multipliers (ADMM)-based iterative
approach. This method yields closed-form expressions and effectively suppresses
interference signals. Simulation outcomes affirm that our RIS-ADMM method
surpasses existing techniques in DOA estimation accuracy while maintaining low
computational complexity. The code for the proposed method is available online
\url{https://github.com/chenpengseu/RIS-ADMM.git}.Comment: 5 page
Semiparametric proximal causal inference
Skepticism about the assumption of no unmeasured confounding, also known as
exchangeability, is often warranted in making causal inferences from
observational data; because exchangeability hinges on an investigator's ability
to accurately measure covariates that capture all potential sources of
confounding. In practice, the most one can hope for is that covariate
measurements are at best proxies of the true underlying confounding mechanism
operating in a given observational study. In this paper, we consider the
framework of proximal causal inference introduced by Tchetgen Tchetgen et al.
(2020), which while explicitly acknowledging covariate measurements as
imperfect proxies of confounding mechanisms, offers an opportunity to learn
about causal effects in settings where exchangeability on the basis of measured
covariates fails. We make a number of contributions to proximal inference
including (i) an alternative set of conditions for nonparametric proximal
identification of the average treatment effect; (ii) general semiparametric
theory for proximal estimation of the average treatment effect including
efficiency bounds for key semiparametric models of interest; (iii) a
characterization of proximal doubly robust and locally efficient estimators of
the average treatment effect. Moreover, we provide analogous identification and
efficiency results for the average treatment effect on the treated. Our
approach is illustrated via simulation studies and a data application on
evaluating the effectiveness of right heart catheterization in the intensive
care unit of critically ill patients
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