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Landslide damage has been reported in many limestone areas in Europe, where the population lives close to limestone areas, and in Guilin in southern China and Ha Long in Vietnam, which are known for their unique limestone landscapes. There are few studies on the mechanism and type of landslide motion in and around such limestone areas. The lack of basic data is a problem for risk assessment and countermeasures in limestone areas. In this study, we summarized the causes and mechanisms of landslide occurrence, including geology and groundwater, focusing on six landslides that occurred in limestone areas in northern Vietnam, and classified them into six types of landslide movement. In the case of Japan, the occurrence of landslides in limestone areas is rare despite the wide distribution of limestone, and it is difficult to classify the type of movement. Differences in the landslide mechanisms are caused by the difference between limestones generated in the pelagic environment of Japan and limestones developed along the Tethys Sea coast, which are mixed with pelitic rocks as shallow-water sediments in Europe, China, and Vietnam. It is necessary to elucidate the relationship between landslides and the formation environment and sedimentary characteristics of limestone as an accretionary prism based on comparisons of a wide range of cases in future studies.

Titanium-based alloy products manufactured by Selective Laser Melting (SLM) have been widely used in biomedical applications, owing to their high biocompatibility, significantly good mechanical properties. In order to improve the Ti–6Al–4V SLM-fabricated part quality and help the manufacturing engineers choose optimal process parameters, an optimization methodology based on an artificial neural network was developed to relate four key process parameters (laser power, laser scanning speed, layer thickness, and hatch distance) and two target properties of a part fabricated by the SLM technique (density ratio and surface roughness). A supervised learning deep neural network based on the backpropagation algorithm was applied to optimize input parameters for a given set of quality part outputs. Several methods were utilized to solve undesired problems occurring during neural network training to increase the model accuracy. The model’s performance was proven with a value of R2 of 99% for both density ratio and surface roughness. A selection system was then built, allowing users to choose the optimal process parameters for fabricated products whose properties meet a specific user requirement. Experiments performed with the optimal process parameters recommended by the optimization system strongly confirmed its reliability by providing the ultimate part qualities nearly identical to those defined by the user with only about 0.9–4.4% of errors at the maximum. Finally, a graphical user interface was developed to facilitate the choice of the optimum process parameters for the desired density ratio and surface roughness.

Purpose Pricing on the online booking systems is a difficult task for the host, the systems usually set the prices that are lower than the general premises and quality, and that only gives benefits to the system by easily attracting the customer to use the service. The setting price of the new accommodation is often based on location, the number of beds, type of house and so on. The main problem is to predict the most reasonable price for the host. This paper aims to study the use of machine learning and sentiment analysis for predicting the price of online booking systems. Design/methodology/approach In particular, an empirical study is performed first for some well-known classification models for the problems. The authors then propose to apply k-means, a clustering technique, together with Gradient Boost and XGBoost models to improve the prediction performance. Experiments are conducted and tested for real Airbnb data sets collected in London City. Findings Experimental results are given and compared to show that the authors’ method outperforms to an updated method. Originality/value The authors use k-means and sampling together with Gradient Boost and XGBoost models to improve the prediction performance.

In this paper, we propose a heuristic search algorithm based on maximum conflicts to find a weakly stable matching of maximum size for the stable marriage problem with ties and incomplete lists. The key idea of our approach is to define a heuristic function based on the information extracted from undominated blocking pairs from the men’s point of view. By choosing a man corresponding to the maximum value of the heuristic function, we aim to not only remove all the blocking pairs formed by the man but also reject as many blocking pairs as possible for an unstable matching from the women’s point of view to obtain a solution of the problem as quickly as possible. Experiments show that our algorithm is efficient in terms of both execution time and solution quality for solving the problem.

The structural and magnetic properties of Bi0.5La0.5Fe1−xCrxO3−δ (x = 0, 0.05, 0.10, 0.20, and 0.40) compounds synthesized by a solid-state reaction method have been investigated. Rietveld refinement of x-ray and neutron powder diffraction data revealed a nonpolar orthorhombically distorted perovskite Pnma structure with long-range G-type antiferromagnetic (AFM) order in the studied samples. It was observed that substitution by Cr strongly influenced the morphology, crystalline, and magnetic properties of the samples. Interestingly, Cr doping led to an abrupt increase in the crystallite size from 31 nm for x = 0 to 740 nm for x = 0.40. This size change was accompanied by a decrease of microstrain by about twofold and a sudden change of the structural parameters. Magnetization measurements indicated the coexistence of ferromagnetic (FM) clusters with long-range AFM order. It was established that Cr doping leads to a suppression of the magnetic states. More interestingly, all of the samples demonstrated a spontaneous large exchange bias (EB) effect at room temperature, which is of great interest from the viewpoint of practical applications. The EB effect originates from pinning of uncompensated spins at the interfaces between FM clusters and the AFM matrix.

The purpose of this work is to find an optimal combination of the input parameters when electrical discharge machining (EDM) cylindrical shaped parts so that both the surface roughness and the electrode wear are minimum. In this study, four input parameters including the pulse on time, the pulse off time, the current, and the serve voltage were taken into account. Experimental plan was designed based on L9 orthogonal array. Also, Taguchi method and Grey Relational Analysis (GRA) were joined for solving the multiobjective optimization problem and to find optimum input parameters. Experiments with optimal input parameters were performed for proving the predicted model. The experimental results of the surface roughness and the electrode wear matched with the calculated model. This indicates the proposed models can be used for practice.

Tracking dialogue states to better interpret user goals and feed downstream policy learning is a bottleneck in dialogue management. Common practice has been to treat it as a problem of classifying dialogue content into a set of pre-defined slot-value pairs, or generating values for different slots given the dialogue history. Both have limitations on considering dependencies that occur on dialogues, and are lacking of reasoning capabilities. This paper proposes to track dialogue states gradually with reasoning over dialogue turns with the help of the back-end data. Empirical results demonstrate that our method outperforms the state-of-the-art methods in terms of joint belief accuracy for MultiWOZ 2.1, a large-scale human--human dialogue dataset across multiple domains.

This study aims to minimize electrode wear (EW) and maximize material removal rate (MRR) in powder mixed electrical discharge machining (PMEDM) process of 9CrSi alloy steel with silicon carbide powder. To achieve these objectives, Taguchi method and Grey Relational Analysis (GRA) are applied to optimize one two-level and four three-level PMEDM process parameters, including Ton, Toff, CP, IP and SV in eighteen experiments based on an orthogonal array L18 (21 and 43). Results have provided a set of optimal PMEDM process parameters in which Ton has the strongest effect on SW and MRR while that of CP is insignificant. The obtained minimum EW and maximum MRR have been verified and proven by a PMEDM experiment using optimal process parameters. The proposed method can be further applied to optimize other PMEDM process parameters for different objectives.

In electrical discharge machining (EDM) powder material can be mixed into the dielectric fluid to improve quality of machining surface of components. Therefore, finding suitable input parameters of this process becomes an important task. This paper presents a methodology to find the optimum input factors of the EDM process when adding nanosilicon carbide powder into the dielectric fluid for processing cylindrical shaped parts. In this research, the Taguchi method was used for experiment design in order to investigate the effect of the input parameters on the surface roughness. Also, optimum input factors for minimum surface roughness (RS) was proposed. The result from the deviation of SRbetween the analysis and the experiment demonstrates that the optimum input parameters are helpful to predict the value of surface roughness. Therefore, this can increase the economic and technical effectiveness in EDM process.

This paper presents a work on the effect of Powder Mixed Electric Discharge Machining (PMEDM) parameters on the machining time when machining cylindrical shaped parts made from 90CrSi alloy steel. Five parameters including pulse on time Ton, powder concentration Cp, pulse off time Toff, pulse current IP and server voltage SV are explored their contribution on machining time by using the Taguchi method in eighteen experiments based on an orthogonal array L18 (21 and 34). Based on ANOVA analysis, an optimum model of the machining time was proposed. The model was well verified by comparing with the experiment, and it, therefore can be used for further studies in the PMEDM process.

Entity-centric knowledge graphs (KGs) are now popular to collect facts about entities. KGs have rich schemas with a large number of different types and predicates to describe the entities and their relationships. On these rich schemas, logical rules are used to represent dependencies between the data elements. While rules are useful in query answering, data curation, and other tasks, they usually do not come with the KGs. Such rules have to be manually defined or discovered with the help of rule mining methods. We believe this rule-collection task should be done collectively to better capitalize our understanding of the data and to avoid redundant work conducted on the same KGs. For this reason, we introduce RuleHub , our extensible corpus of rules for public KGs. RuleHub provides functionalities for the archival and the retrieval of rules to all users, with an extensible architecture that does not constrain the KG or the type of rules supported. We are populating the corpus with thousands of rules from the most popular KGs and report on our experiments on automatically characterizing the quality of a rule with statistical measures.

International audience; In hypothetical accidental conditions, zirconium-based nuclear fuel claddings can absorb high hydrogen contents (up to several thousand wppm) and be exposed to high temperatures (βZr phase temperature range) before being cooled. This paper thoroughly investigates the microstructural and microchemical evolutions that take place in such conditions. Two zirconium-based alloys and unalloyed zirconium were pre-charged with hydrogen at various contents up to 3300 wppm and heat-treated at 1000 or 850 °C. Neutron diffraction analyses were performed in situ upon slow cooling from 700 °C and at room temperature. In the materials containing 3300 wppm of hydrogen, βZr progressively transforms into αZr during slow cooling then extensively transforms into αZr and δZrH2-x hydrides precipitate via a eutectoid reaction. Thermodynamic predictions at equilibrium are in good agreement with the experimental results. However, depending on the cooling scenario and the average hydrogen content, the precipitation of γZrH hydrides, potentially metastable, is evidenced below 350 °C and a significant amount of hydrogen can remain in solid solution in αZr. These metallurgical evolutions and the evolution of the different phase lattice parameters are strongly influenced by the partitioning of oxygen and hydrogen (revealed by electron probe and elastic recoil detection microanalyses) that occurs during the βZr to αZr transformation and hydride precipitation.

This paper deals with the effect of input parameters of Powder Mixed Electric Discharge Machining (PMEDM) process on the surface roughness when processing cylindrical shaped parts. In this work, the workpiece material is 90CrSi alloy tool steel and the nanopowder is silicon carbide. Also, five input parameters including the pulse on time, the pulse off time, the powder concentration, the current and the server voltage were selected to investigate their influence on the surface roughness. Taguchi method and ANOVA analysis were used and the effect of input parameters on the surface roughness was presented. Moreover, optimum input parameters for minimum surface roughness was suggested.

The straightening of low-rigidity cylindrical components by transverse rolling with smooth plates is considered. The influence of absolute reduction after straightening on the following parameters of the products is studied: the linearity and diametric precision of the product; and the microstructure, hardness, and hardened depth of the strengthened part.

This study presents a prediction study of the surface hardness in surface grinding ASIS 1045 steel. Base on the experimental data on the changes in characteristics of steel in the heat treatment processes, the relationship between the surface hardness and the impacted temperature in surface was found. Besides, the relationship between the cutting temperature and the technology parameters in the grinding was created. The surface hardness was then formulated as a function of the technology parameters in the grinding processes such as the depth of cut, the grinding wheel speed, the workpiece speed, etc. The proposed model was verified by comparing the predicted and measured results of surface hardness. This model can be used to predict the surface hardness when surface grinding.

This paper introduces an experimental study on the influence of electrical discharge machining (EDM) cylindrical shaped parts made of 90CrSi tool steel. In this work, some experiments were designed and analysed based on Taguchi method. Also, four input parameters including the pulse on time, the pulse off time, the current, and the server voltage were investigated. The influence of these parameters on the surface roughness were estimated by analysing variance. In addition, the optimum input parameters were found for getting the minimum surface roughness.

This paper introduces an optimization study on electrode wear when electrical discharge machining (EDM) cylindrical shaped parts made from 90CrSi. In the study, the experiments were performed and analyzed by using Taguchi method. The input parameters of the experiments were the pulse on time, the pulse off time, the current, and the server voltage. The effect of input parameters on the electrode wear were evaluated by analyzing variance. Also, the optimum values of the input parameter were proposed for getting the minimum electrode wear.

This paper aims to investigate the effect of process parameters on the surface roughness in suface grinding 90CrSi tool steel. In this paper, many process parameters including the coolant concentration, the coolant flow, the cross feed, the table speed and the depth of cut were taken into account. Based on conducting and analysing 25 experiments which were created by using full factorial design, the influence of the process parameters on the surface roughness was evaluated. Also, a predicted model to calculate the surface roughness was proposed.

This paper introduces a study on multi-criteria optimization of the dressing parameters in surface grinding for 90CrSi tool steel. The aim of the study is to minimize the surface roughness, the normal shear force and maximize the grinding wheel life by using Taguchi method and Grey Relational Analysis (GRA). This multi-objective optimization is obtained by optimizing four four-level and two two-level dressing parameters in sixteen experiments based on an orthogonal array L16(44×22). From the results of the study, the optimum dressing parameters were proposed. Also, to evaluate the optimum dressing model, an experiment was performed. The results of the comparison between the predicted model and the experiment show that the proposed model has been proven and it can be used for further applying of surface grinding.

Grinding cost is an essential factor in a grinding process. In external cylindrical grinding, there has been an absence of various input grinding process parameters which have significant effects on the grinding cost. This paper presents an optimization of the grinding cost to determine the optimum exchanged grinding wheel diameter based on the seven input grinding parameters consisting of the initial grinding wheel diameter, the grinding wheel width, the wheel life, the radial grinding wheel wear per dress, the total depth of dressing cut, the machine tool hourly rate, and the grinding wheel cost. Combined with the screening experiments, the influence of the grinding parameters on the optimum exchanged grinding wheel diameter for the external cylindrical grinding process was examined. In addition, the effect of the interactions between the input grinding parameters was also evaluated. Finally, the regression equation for computing the optimum exchanged grinding wheel diameter was introduced. Therefore, the proposed model can be further applied for the external grinding process effectively.

This study aims to propose a method to calculate optimum exchanged grinding wheel diameter to minimize grinding cost in grinding surface process for stainless steel. The interactions of the grinding cost and optimum exchanged grinding wheel diameter have been analyzed and presented in mathematical formulae. To obtain the minimal grinding cost, the optimal exchanged grinding wheel diameter has been determined by investigating six two-level grinding process parameters including initial grinding wheel diameter, total dressing depth, radial grinding wheel wear per dress, wheel life, machine tool hour and grinding wheel cost. Based on 26 experiments conducted in computational program, the optimal exchanged grinding wheel diameter is presented as a function of these grinding parameters. This developed model has been verified and proven by experimental results. The proposed method of calculation of the optimum exchanged grinding wheel diameter can be applied in practice to reduce the grinding cost.

To restore the shape of low-stiff cylindrical parts such as shafts and axles, straightening by transverse bending with the subsequent processing of workpieces by the method of surface plastic deformation based on the transverse burnishing with smooth plates is proposed. The experimental and calculated results are presented to determine the effect of absolute compression on the main characteristics of the quality of the surface layer of parts such as surface roughness and residual stresses. The analysis of experimental data for the evaluation of the parts after straightening by transverse burnishing showed the following positive changes: a sharp decrease in the initial roughness, the formation of equilibrium residual compressive stresses in the surface layers and ensuring stabilization of the accuracy of the processed part in size and shape. Depending on the magnitude of the absolute reduction, the surface quality increases by 2–3 classes, and rather large compressive residual stresses are formed (up to 375 MPa). The results of the work justify recommending the proposed method of straightening by transverse burnishing with smooth plates for implementation into the technology of machine part restoration.

Straightening by transverse bending followed by hardening by surface plastic deformation based on transverse spinning of cylindrical parts by flat plates is suggested to restore the shape of distorted low-rigidity cylindrical parts, such as shafts and axles. The Ansys Workbench software package is used to estimate the state of stress in a cylindrical part during transverse straightening. The distributions of the working and residual stresses over the cross section of a cylinder are obtained as a function of the relative reduction.

International audience; During hypothetical loss-of-coolant accidents (LOCA), zirconium-based nuclear fuel claddings can be exposed to high temperatures in the beta(Zr) phase domain and absorb substantial amounts of hydrogen (up to about 3000 weight ppm) and oxygen (up to about 1 weight %). This paper provides novel data about the combined effects of high hydrogen and oxygen contents on the mechanical behavior of the (prio-r)beta(Zr) phase, as a function of temperature, upon cooling from the beta(Zr) phase temperature range. A protocol was developed to homogeneously charge Zircaloy-4 cladding tubes at different hydrogen contents, up to 3200 weight ppm, and oxygen contents, between 0.13 and 0.9 wt%. Tensile tests were then performed at various temperatures between 700 degrees C and 30 degrees C upon cooling from the beta(Zr) domain. The results show that the mechanical behavior strongly depends on the testing temperature and the hydrogen and oxygen contents. Relationships are proposed to describe the macroscopic ductile-to-brittle transition and the mechanical behavior of the material as a function of temperature, hydrogen and oxygen contents. The predictions based on these relationships are compared to selected data from the literature obtained on claddings oxidized at high temperature, including results from semi-integral LOCA tests. Also, it is shown that considering the combined effects of hydrogen and oxygen is necessary to interpret the material's mechanical behavior, particularly the embrittlement of claddings subjected to LOCA-relevant secondary hydriding.

A statistical moment method has been applied to study the melting of defective face-centered cubic (FCC) interstitial alloy γ-FeC under pressure up to 100 GPa. The theory of melting is based on the absolute stability limiting condition of the crystalline state. The relationship between the pressure, temperature, and concentration of equilibrium vacancies at the melting point of alloy γ-FeC is discussed and evaluated. The numerical results in limit cases are in good agreement with experiments and calculations by other authors, allowing reliable prediction of the melting features of alloy γ-FeC at high pressures.

openaire: EC/H2020/671650/EU//mmMAGIC In this paper, we parameterize an excess loss-based multipath component (MPC) cross-polarization ratio (XPR) model in indoor and outdoor environments for above-5-GHz frequency bands. The results are based on 35 measurement campaigns in several frequency bands ranging from 5 to 80 GHz. A conventional XPR model of an MPC assuming a constant mean value fits our measurements very poorly and moreover overestimates the depolarization effect. Our measurements revealed a clear trend that the MPC XPR is inversely proportional to the excess loss in reference to the free-space path loss. The model is physically sound as a higher loss is attributed to more lossy interactions or to a greater number of interactions with objects, leading to a greater chance of depolarization. The measurements furthermore showed that the MPC XPR is not strongly frequency or environment dependent. In our MPC XPR model, an MPC with zero-dB excess loss has a mean XPR of 27 dB. The mean XPR decreases half-a-dB as the excess loss increases by every dB and the standard deviation around the mean is 7 dB. The model is applicable to existing channel models to reproduce realistic MPC XPRs for the above 5-GHz radio links.

One of the most studied photoluminescence emission peaks of anatase titanium dioxide (TiO2) is green, located at about 520 nm, which is assigned to the radiative recombination between a mobile electron in the conduction band and oxygen vacancy defect as a trapped hole in the bandgap. Composite materials of TiO2 with graphene are normally shown by the gradual quenching of photoluminescence intensity as a result of carrier lifetime extension, which is important to enhance photocatalytic activity. Herein we report an observation of the intensity enhancement of the green PL emission in a composite TiO2 nanotube (TNT) and graphene produced through facile hydrothermal synthesis. The heterojunction formation of graphene and TNT makes the excited photoelectrons easy to diffuse from TNT to graphene. Hence, the recombination rate of mobile electrons in graphene and trapped holes located on the nanotube surface is enhanced due to the high mobility of electrons in graphene.

The intended form of relatively flexible cylindrical parts (shafts and axles) may be restored by straightening by flexure under a distributed load, with subsequent strengthening of the workpiece by surface plastic deformation based on transverse rolling between flat plates. It is well known that the nonequilibrium stresses are generated in the whole workpiece after straightening by transverse flexure, and the part is eventually deformed again. Therefore, the workpieces should be additionally straightened with surface plastic deformation after straightening by flexure. We use transverse rolling by flat plates for that purpose. The aim in the present work is to determine the capture conditions and the stress state of the workpiece in transverse rolling of cylindrical parts between flat plates. The mathematical analysis is based on the theory of an elastoplastic solid; ANSYS Workbench software is employed. A new method is proposed for control of stress state in straightening of cylinderical workpieces. The limiting capture angle α ranging 2–8 degrees and the maximum absolute reduction depending on friction coefficient and on the diameter of workpiece are obtained. The optimum reduction varies ΔH = 0.07–0.15 mm. The calculation data show that the stress state of uniform extension occurs at the center in the workpiece cross section after transverse rolling, and the stress state of reduction is formed at the peripheral areas of the workpiece. The straightening method of transverse rolling between flat plates eliminates crack formation and destruction of the material in the central area of the cylindrical parts.

Relatively flexible cylindrical parts (shafts and axles) may be straightened by loads produced by different stresses in different distributions. A promising method is straightening by flexure under a distributed load, with subsequent strengthening of the workpiece by surface plastic deformation based on transverse rolling between flat plates. The goal in the present work is to determine the stress state of the workpiece in transverse straightening so as to select the best type of load and treatment conditions. The mathematical analysis is based on the theory of an elastoplastic solid; ANSYS Workbench software is employed. Effective methods of loading in the transverse straightening of cylindrical parts are determined. Analytical calculations yield the residual stress corresponding to straightening of the cylindrical parts. The residual stress required for straightening depends on the initial flexure, the material in the workpiece, and its size. The stress state of cylindrical parts is determined for different types of transverse loading. The flexural stress for straightening of a shaft under a distributed load is less than the stress due to a transverse force. To straighten a rod (diameter 10 mm, length 200 mm) with initial flexure 0.5 mm, flexural stress of about 370 MPa must be created. In the transverse straightening of cylindrical parts, flexure under the action of a distributed load is an effective loading method. Limiting flexural coefficients of 5.3–5.5 are obtained for all values of the shaft rigidity in straightening by transverse flexure under a distributed load when l/L = 0.8. The proposed mathematical model correctly determines the residual stress corresponding to straightening of the cylindrical parts. The formula derived for calculating the total flexure and determining the effective load may be recommended for practical use in production conditions so as a ensure precise straightening of relatively flexible parts such as shafts.

The statistical moment method is used to study the melting of defective interstitial AB alloys, where A is the main element and B is an interstitial atom, with a body-centered-cubic (BCC) structure. The melting temperature of the AB alloy with defects is obtained from the temperature of absolute stability for the crystalline state and the equilibrium vacancy concentration. Numerical calculations are performed for the interstitial alloys TaSi and WSi. Our calculated results are in good agreement with other calculations.

The effect of Ni substitution on the magnetic properties and the critical behavior of La0.7Sr0.3Mn1−xNixO3 compounds, which were prepared by the solid-state reaction method has been investigated. Based on our investigations of the temperature and the magnetic field dependences of magnetization M(T, H) data, it is shown that the Curie temperature ( $$ T_{\rm{C}}$$ ) of La0.7Sr0.3Mn1−xNixO3 compounds will be shifted toward room temperature with increasing Ni concentration (x), $$T_{\rm{C}}$$ = 359–307 K for x = 0.0–0.1. By using the modified Arrott plots and the Kouvel–Fisher methods together with $$M(H,T)$$ data in the vicinity of the ferromagnetic (FM)–paramagnetic phase transition, the critical exponents (β, γ, and δ) have been determined. Our results show the existence of a short-range FM order in the undoped sample (x = 0). The values of β, γ, and δ will be shifted gradually toward those of the mean-field theory when x increases, suggesting that the long-range FM order is favored in Ni-doped samples. The results calculated on the effective exponents of $$\beta_{\rm{eff}} (\varepsilon )$$ and $$\gamma_{\rm{eff}} (\varepsilon )$$ in the asymptotic region indicate the existence of a magnetic disorder in all the samples.

This paper presents a study on optimum calculation of the exchanged diameter of grinding wheels in internal grinding of stainless steel. In this study, the effects of the grinding process parameters including the initial diameter, the total depth of dressing cut, the wheel life, the radial grinding wheel wear per dress and the ratio between the length and the diameter of the workpieces on the exchanged grinding wheel diameter were explored. The influences of cost factors including the machine tool hourly rate and the grinding wheel cost were also investigated. To evaluate the effects of these parameters on the optimum exchanged grinding wheel diameter, a simulation experiment was created and performed by and a computer program. A proposed model to determine the optimum exchanged grinding wheel diameter was given based on the results of the study.

This paper introduces a study on optimum determination of exchanged grinding wheel diameter when external grinding of stainless steel. In this study, the influences of grinding process parameters including the initial grinding wheel diameter, the total dressing depth, the radial grinding wheel wear per dress and the wheel life on the exchanged grinding wheel diameter were investigated. Also, the effect of cost parameters including the grinding wheel cost and the machine tool hourly rate were investigated. To estimate the influence of these parameters on the optimum exchanged grinding wheel diameter, a simulation experiment was designed and it was performed by a computer program. Based on the results of the experiment, a formula for calculation of the optimum exchanged diameter was introduced

This study has been done to optimize the dressing parameters in internal cylindrical grinding process for 9CrSi tool steel to minimize surface roughness and maximize material removal rate (MRR) using Taguchi method and Grey Relational Analysis (GRA). This multi-objective optimization is obtained by optimizing five three-level and one six-level dressing parameters in eightteen experiments based on an orthogonal array L18(35×16). The results show that the optimal dressing parameters to obtain the minimal roughness average and maximal MRR are the coarse dressing depth of 0.02 mm, the coarse dressing times of 1 time, the fine dressing depth of 0.005 mm, the fine dressing times of 3 times, the non-feeding dressing of 5 times and the dressing feed rate of 1.4 m/min, respectively. The differences of the roughness average and MRR from the experiments and the predict model are small. Thus, the proposed method has been proven and it can be further applied in other studies.

At about 12:00 a.m., on October 13, 2020, a rapid rotational landslide induced by rainfall swept over Ranger Station-7 in Phong Xuan commune, Phong Dien district, Thua Thien Hue province, Vietnam, claiming the lives of 13 rescue team members. This paper presents an overview of the fatal landslide at Ranger Station-7. The analysis indicates that the entire landslide had a volume of approximately 81,550 m3. The observed topographical features indicate that the landslide mass consists of lower and upper blocks. The lower block of the landslide mass started sliding first; the movement was then followed by the slide of the upper block.

Spin-driven ferroelectricity phenomena have drawn great interest in the scientific community due to potential application in spintronics and their complex physical mechanisms. A noticeable example of this is multiferroic $\mathrm{BaYFe}{\mathrm{O}}_{4}$ that exhibits an unconventional magnetoelectric (ME) coupling due to the uncorrelated behavior of the ferroelectric and cycloidal states under an applied magnetic field. To shed more light on this spin-driven ME effect, a high-quality sample of $\mathrm{BaYFe}{\mathrm{O}}_{4}$ was synthesized by a standard solid-state reaction method, and its high-field (up to 9 T) magnetic properties have been systematically investigated by means of magnetometry, magnetocaloric effect, and M\"ossbauer measurements over a wide temperature range (5--400 K). In addition, its crystal and magnetic structures have been studied using x-ray and neutron powder diffraction. Results obtained indicate that Fe spins form a long-range spin density wave (SDW) antiferromagnetic (AFM) order at ${T}_{\mathrm{N}1}\ensuremath{\sim}50\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, which transforms into the cycloidal AFM order at ${T}_{\mathrm{N}2}\ensuremath{\sim}35\phantom{\rule{0.16em}{0ex}}\mathrm{K}$. A spin-glass-like state emerges below ${T}^{*}\ensuremath{\sim}17\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, and coexists with the long-range cycloidal AFM one in this temperature range. Magnetocaloric and M\"ossbauer measurements consistently confirm the robustness of both the long-range SDW and cycloidal AFM orders under applied magnetic fields up to 6 T, whereas the spin-glass state is converted into the ferromagnetic (FM) state when the applied magnetic field exceeds 1 T. These findings pinpoint the fact that the magnetic field evolution of spin correlations from the AFM to FM character in the spin-glass state is responsible for the magnetic field dependence of ferroelectricity in $\mathrm{BaYFe}{\mathrm{O}}_{4}$.

Multi-domain dialogue state tracking (DST) is a critical component for monitoring user goals during the course of an interaction. Existing approaches have relied on dialogue history indiscriminately or updated on the most recent turns incrementally. However, in spite of modeling it based on fixed ontology or open vocabulary, the former setting violates the interactive and progressing nature of dialogue, while the later easily gets affected by the error accumulation conundrum. Here, we propose a Recursive Inference mechanism (ReInf) to resolve DST in multi-domain scenarios that call for more robust and accurate tracking capability. Specifically, our agent reversely reviews the dialogue history until the agent has pinpointed sufficient turns confidently for slot value prediction. It also recursively factors in potential dependencies among domains and slots to further solve the co-reference and value sharing problems. The quantitative and qualitative experimental results on the MultiWOZ 2.1 corpus demonstrate that the proposed ReInf not only outperforms the state-of-the-art methods, but also achieves reasonable turn reference and interpretable slot co-reference.

Nowadays, Wireless Vehicular Ad‐Hoc Network (VANET) has become a valuable asset for transportation systems. However, this advanced technology is characterized by highly distributed and net...

openaire: EC/H2020/871464/EU//ARIADNE The use of above-100 GHz radio frequencies would be one of promising approaches to enhance the fifth-generation cellular further. Any air interface and cellular network designs require channel models, for which measured evidence of large-scale parameters such as pathloss, delay and angular spreads, is crucial. This paper provides the evidence from quasi-static spatio-temporal channel sounding campaigns at two indoor hotspot (InH) scenarios at 140 GHz band, assuming short-range backhaul connectivity. The measured two InH sites are shopping mall and airport check-in hall. Our estimated omni-directional large-scale parameters from the measurements are found in good match with those of the Third Generation Partnership Project (3GPP) for new radios (NR) channel model in InH scenario, despite the difference of assumed link types and radio frequency range. The 3GPP NR channel model is meant for access links and said to be valid up to 100 GHz, while our measurements cover short-range backhaul scenarios at 140 GHz. Wefound more deviation between our estimated large-scale parameters and those of the 3GPP NR channel model in the airport than in the shopping mall.

Nowadays, the payment scheme of European Day-Ahead Market is based on the market clearing price by running the Pan-European Hybrid Electricity Market Integration Algorithm. However, this conventional payment scheme is challenging because of the non-convexity and the short computation time requirement. Thus, the aim of this work is to propose a new clearing model in order to mitigate this challenge. The model is based on make-whole payment mechanism and it includes two major steps: (i) maximizing social welfare and (ii) achieving a Walrasian equilibrium by the “minimum-uplift approach”. The proposed model is validated and investigated by two case studies: one is an artificially created Day-Ahead Market session containing all type of bids encountered in Europe and containing a very large number of bids to stress the algorithm and the other is a reduced, but realistic, model of European market where real data from February to December of 2017 were considered. The tests show a consistent improvement of the numerical performances of the proposed model with respect to the conventional one while the economic performance is not altered, but is slightly improved. Moreover, because the tests are based on real data during a long period of time, the results show that proposed model is very promising for the real application.

In microgrids, distributed generators that cannot be dispatched, such as a photovoltaic system, need to control their output power at the maximum power point. The fluctuation of their output power should be minimized with the support of the maximum power point tracking algorithm under the variation of ambient conditions. In this paper, a new maximum power point tracking method based on the parameters of power deviation (ΔPPV), voltage difference (ΔVPV), and duty cycle change (ΔD) is proposed for photovoltaic systems. The presented algorithm achieves the following good results: (i) when the solar radiance is fixed, the output power is stable around the maximum power point; (ii) when the solar radiance is rapidly changing, the generated power is always in the vicinity of maximum power points; (iii) the effectiveness of energy conversion is comparable to that of intelligent algorithms. The proposed algorithm is presented and compared with traditional and intelligent maximum power point tracking algorithms on the simulation model by MATLAB/Simulink under different radiation scenarios to prove the effectiveness of the proposed method.

This paper describes the control problem of a multi-degree nonlinear mechanical plant with an unknown disturbance. An unknown disturbance is represented as output of a linear autonomous model with unknown constant parameters. To solve the problem of adaptive disturbance compensation, an adaptive observer of external disturbance was applied. In this paper is proposed an algorithm of nonlinear robust control of a Lagrangian plant, synthesized on the integrator bypass method, combined with the evaluation of an adaptive disturbance observer. The simulation of the designed nonlinear robust control with an adaptive disturbance observer was held using MATLAB/Simulink.

The farthest-first-traversal (fft) algorithm originally was used by Rosenkrantz et al. in an analysis of heuristics for the traveling salesman problem. This algorithm has been extensively studied for several sampling techniques. In this work, we present a modification of ProTraS algorithm given by Ros and Guillaume, which is also based on the fft algorithm, for sampling datasets for both k-means and k-median clustering algorithms. Unlike ProTraS, proposed algorithm takes the size of samples as an input. The algorithm is implemented in the Spark platform and tested for benchmark datasets. We also estimate the algorithm by comparing with the adaptive sampling and lightweight coreset algorithms, using the adjust Rand index.

This paper presents an experimental study in Vietnamese constituency syntactic parsing. We first compare results of two recent constituency parsers on a Vietnamese corpus, a shift-reduce constituency parser and a neural parser. We then integrate distributed word representations into the shift-reduce parser to improve its \(F_1\) score. We also report a new state-of-the-art parsing score for Vietnamese with \(F_1\) score of 80% in the neural parser. Finally, we perform error analysis on a sample of 100 sentences for the neural parser, which helps categorize ambiguous and difficult constructions inherent to the problem of Vietnamese syntactic parsing.

Atmospheric deposition of trace elements in three cities of Vietnam including Hue, Hoi An and Ho Chi Minh in Central and South of Vietnam has been studied in this work by moss technique. Thirty samples of the local moss Barbula indica were collected in these cities and the concentrations of thirty heavy elements were determined by neutron activation analysis at the reactor IBR-2 of the Frank Laboratory of Neutron Physics of the Joint Institute for Nuclear Research located in Dubna, Russia. Concentrations of thirty elements were determined in each sample. Factor analysis has been applied to the concentration data and five main factors, which characterized five possible sources of the air pollution affecting the investigated areas have been identified. The correspondence between the research results and the reality of the air pollution in the studied sites has proved high possibility of the method for studying air pollution in Vietnam.

In this investigation, we have studied the crystal structure and magnetic properties of Zn doped Bi0.84La0.16FeO3 (x = 0.02–0.1) ceramics at the morphotropic phase boundary of rhombohedral and orthorhombic phases. Rietveld refinement of the obtained XRD patterns and Raman spectroscopy confirm the presence of multiphases crystal structure of R3c rhombohedral and Pbam orthorhombic. Room temperature magnetic measurements showed weak ferromagnetic ordering and enhancement in magnetization and coercivity with dominating of orthorhombic phase. The isothermal structural transition from R3c to Pbam is caused for the decrease in magnetization and the increase in coercivity.

Future wireless networks are expected to operate in both the centimeter-wave and millimeter-wave bands. It is thus necessary to provide an accurate characterization of the {em joint} channel properties in the two bands. Shadow fading is an important characteristic of wireless channels as it impacts achievable data rates and in particular outage probabilities. In this paper, we propose cross-band correlation models that can be used to capture the correlation over space and frequency. The models are designed to reduce to existing correlation models in the case of a single-band, which enables reuse of the large existing literature for (single-band) shadowing models. We extract and report the parameters of the proposed models in a micro-cellular environment. The important finding from our proposed models is that the cross-band spatial correlation function may not be derived just by scaling a single-band correlation function.

A novel magnetic nanocomposite of iron oxide nanoparticles encapsulated by carbon layer (Fe3O4@C) was prepared by using a two-step process of coprecipitation and hydrothermal method. The iron oxide nanoparticles with an average crystalline diameter of ∼20 nm was used, whereas the concentration of C was varied from 1.25 to 10% by adjusting the mass ratio of glucose as a carbon source. We found that the arsenate removal efficiency of the Fe3O4@C nanocomposite increased with increasing C concentration, reached a maximum at 1.25% C concentration, and finally decreased for further increase in the C content. The adsorption kinetics process of the Fe3O4@C nanocomposite was well fitted with both Langmuir and pseudo-second-order kinetic models. In contrast, the heating efficiency of Fe3O4 nanoparticles was progressively reduced with increasing C content, regardless of the AC field value. Our study indicates the use of carbon as an encapsulator for iron oxide nanoparticles is very promising as an advanced absorbent for removal of environmental pollutants, such as arsenate As(V) while it is not ideal for magnetic hyperthermia based cancer therapy.

Currently, the integration of European Electricity Market (EEM) has led to a single European Day-Ahead Market (DAM) with multiple-areas considered as bidding zones. In the near future, the EEM will spread to the Intra-day and Balancing market. To operate the DAM, a market clearing tool (algorithm) has been developed by market operators. The development of this algorithm corresponds to three primary principles: (i) one single framework, (ii) robust operation, and (iii) individual accountability. However, this algorithm is not available to the research community. In this paper, the authors develop a complete European DAM model in General Algebraic Modelling System (GAMS), formulating it as a Mix Integer Quadratic Constraint Problem (MIQCP) and iterative procedure, to mitigate the non-convexity of electricity prices across Europe due to the “fill or kill” condition of block, complex and Prezzo Unico Nazionale (PUN) orders. Eventually, two case studies reflecting the current European DAM evaluated the model, aiming to confirm its robustness and reliability.

We demonstrated an effective approach for making NdFe 11 Co alloy. We used a polyol method with ethylene glycol (EG), polyvinylpyrrolidone (PVP), NaBH 4 , FeCl 3 (and/or FeCl 2 ), NdCl 3 , and NaOH for Fe oxide with Nd element according to heat treatment. To obtain NdFe 11 Co alloy products, dried oxide products were heated for solidification, and at 900 °C in Ar gas with CaH 2 . The weight ratio of oxide/CaH 2 is 1:1, and NdFe 11 Co particles are formed by annealing at 900 °C for 1 h. The crystal structure of NdFe 11 Co was identified with the main 2–17 phase and the rich-CoFe phase inside its crystal with grain and grain boundary.