Towards Explainable Conversational Recommender Systems

Explanations in conventional recommender systems have demonstrated benefits in helping the user understand the rationality of the recommendations and improving the system's efficiency, transparency, and trustworthiness. In the conversational environment, multiple contextualized explanations need to be generated, which poses further challenges for explanations. To better measure explainability in conversational recommender systems (CRS), we propose ten evaluation perspectives based on concepts from conventional recommender systems together with the characteristics of CRS. We assess five existing CRS benchmark datasets using these metrics and observe the necessity of improving the explanation quality of CRS. To achieve this, we conduct manual and automatic approaches to extend these dialogues and construct a new CRS dataset, namely Explainable Recommendation Dialogues (E-ReDial). It includes 756 dialogues with over 2,000 high-quality rewritten explanations. We compare two baseline approaches to perform explanation generation based on E-ReDial. Experimental results suggest that models trained on E-ReDial can significantly improve explainability while introducing knowledge into the models can further improve the performance. GPT-3 in the in-context learning setting can generate more realistic and diverse movie descriptions. In contrast, T5 training on E-ReDial can better generate clear reasons for recommendations based on user preferences. E-ReDial is available at https://github.com/Superbooming/E-ReDial

Enhancing CO₂-Cured cementitious binder with Mg-doped γ-C₂S from high-Mg limestone

This study explores the use of Mg-doped γ-C2S, an alternative to conventional Portland cement, to address the environmental impact of the cement industry. γ-C2S, known for low hydration activity, shows promise as a CO2-cured binder. The research investigates Mg substitution in γ-C2S synthesis, utilizing high-Mg limestone resources. Varying Mg/Ca ratios in γ-C2S synthesis promoted bredigite and merwinite phases during calcination, enhancing specific surface area by over 40%. Optimal Mg doping significantly increased carbonation reactivity, resulting in a 20% strength boost (115 MPa) after 24h of CO2 curing. This improvement is attributed to enhanced crystallinity in carbonation products, namely hydromagnesite, nesquehonite, aragonite, and magnesite, leading to microstructure densification. The findings highlight Mg-doping as a promising strategy to enhance the carbonation performance of γ-C2S from high-Mg limestone, offering prospects for sustainable construction materials with reduced CO2 emissions.</p

Symmetry guaranteed Dirac-line semimetals in two-dimensions against strong spin-orbit coupling

Several intriguing electronic phenomena and electric properties were discovered in three-dimensional Dirac nodal line semimetals (3D-DNLSM), which are, however, easy to be perturbed under strong spin-orbit coupling (SOC). While two-dimensional (2D) layers are an emerging material category with many advantages, 2D-DNLSM against SOC is yet to be uncovered. Here, we report a 2D-DNLSM in odd-atomic-layer Bi (the brick phase, another Bi allotrope), whose robustness against SOC is protected by the little co-group C_2v \times Z^T_2, the unique protecting symmetry we found in 2D.Specially, (4n+2) valence electrons fill the electronic bands in the brick phase, so that the Dirac nodal line with fourfold degeneracy locates across the Fermi level. There are almost no other low energy states close to the Fermi level; this allows to feasibly observe the neat DNLSM-induced phenomena in transport measurements without being affected by other bands. In contrast, Other VA-group elements also form the brick phases, but their DNL states are mixed with the extra states around the Fermi level. This unprecedented category of layered materials allows for exploring nearly isolated 2DDNL states in 2D.Comment: Totally 25 pages including main text, methods and supporting information, 4 figures, 8 SI figure

Development of an analytical method to detect cyanide in Chinese liquor by ion chromatography with pulsed amperometric detection

Objective This study aimed to develop an ion chromatography-pulse amperometry (IC-PAD) technique for the identification and quantification of cyanide in Chinese liquor. Methods The real samples from local markets were diluted to 1∶10 with ultrapure water before being injected to IC-PAD. Potassium hydroxide (12 mmol/L) was introduced for gradient elution. Silver electrode was utilized with Ag/AgCl composite reference electrode mode. Three potential wave forms were also involved in the study. Results This method showed good linear responses ranging from 5 to 200 μg/L with satisfactory linear correlation coefficient of 0.999 9. The limit of detection (LOD) was 3.5 μg/L, and the limit of quantitation (LOQ) was 9.5 μg/L in Chinese liquor samples. For different types of Chinese liquor, the recoveries of cyanide in fortified samples (10, 30, 50 μg/L) were from 91.7% to 102.0%. The intra-day relative standard deviation (RSD) was from 2.2% to 4.8%, and the inter-day RSD ranged from 1.5% to 1.9%. The comparison between this proposed method and the GB 5009.36-2016 method showed no statistical difference (P>0.05). Conclusion This technique was performer-friendly and exhibited high reliability and accuracy, which was suitable for the detection of cyanide in real samples

Self calibration of gravitational shear-galaxy intrinsic ellipticity correlation in weak lensing surveys

The galaxy intrinsic alignment is a severe challenge to precision cosmic shear measurement. We propose to self-calibrate the induced gravitational shear-galaxy intrinsic ellipticity correlation (the GI correlation, \citealt{Hirata04b}) in weak lensing surveys with photometric redshift measurement. (1) We propose a method to extract the intrinsic ellipticity-galaxy density cross correlation (I-g) from the galaxy ellipticity-density measurement in the same redshift bin. (2) We also find a generic scaling relation to convert the extracted I-g correlation to the demanded GI correlation. We perform concept study under simplified conditions and demonstrate its capability to significantly reduce the GI contamination. We discuss the impact of various complexities on the two key ingredients of the self-calibration technique, namely the method to extract the I-g correlation and the scaling relation between the I-g and the GI correlation. We expect none of them is likely able to completely invalidate the proposed self-calibration technique.Comment: 14 pages, 4 figures. Heavily expanded version. No changes in major results and conclusions. Accepted to Ap

A Platform for Far-Infrared Spectroscopy of Quantum Materials at Millikelvin Temperatures

Optical spectroscopy of quantum materials at ultralow temperatures is rarely explored, yet it may provide critical characterizations of quantum phases not possible using other approaches. We describe the development of a novel experimental platform that enables optical spectroscopic studies, together with standard electronic transport, of materials at millikelvin temperatures inside a dilution refrigerator. The instrument is capable of measuring both bulk crystals and micron-sized two-dimensional van der Waals materials and devices. We demonstrate the performance by implementing photocurrent-based Fourier transform infrared spectroscopy on a monolayer WTe$_2$ device and a multilayer 1T-TaS$_2$ crystal, with a spectral range available from near-infrared to terahertz range and in magnetic fields up to 5 T. In the far-infrared regime, we achieve spectroscopic measurements at a base temperature as low as ~ 43 mK and a sample electron temperature of ~ 450 mK. Possible experiments and potential future upgrades of this versatile instrumental platform are envisioned.Comment: 13 pages, 6 figures, typos correcte

CSST forecast: impact from non-Gaussian covariances and requirements on systematics-control

The precise estimation of the statistical errors and accurate removal of the systematical errors are the two major challenges for the stage IV cosmic shear surveys. We explore their impact for the China Space-Station Telescope (CSST) with survey area $\sim17,500\deg^2$ up to redshift $\sim4$. We consider statistical error contributed from Gaussian covariance, connected non-Gaussian covariance and super-sample covariance. We find the super-sample covariance can largely reduce the signal-to-noise of the two-point statistics for CSST, leading to a $\sim1/3$ loss in the figure-of-merit for the matter clustering properties ($\sigma_8-\Omega_m$ plane) and $1/6$ in the dark energy equation-of-state ($w_0-w_a$ plane). We further put requirements of systematics-mitigation on: intrinsic alignment of galaxies, baryonic feedback, shear multiplicative bias, and bias in the redshift distribution, for an unbiased cosmology. The $10^{-2}$ to $10^{-3}$ level requirements emphasize strong needs in related studies, to support future model selections and the associated priors for the nuisance parameters.Comment: submitted to MNRA