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排序方式: 共有163条查询结果,搜索用时 22 毫秒
1.
Money laundering has been affecting the global economy for many years. Large sums of money are laundered every year, posing a threat to the global economy and its security. Money laundering encompasses illegal activities that are used to make illegally acquired funds appear legal and legitimate. This paper aims to provide a comprehensive survey of machine learning algorithms and methods applied to detect suspicious transactions. In particular, solutions of anti-money laundering typologies, link analysis, behavioural modelling, risk scoring, anomaly detection, and geographic capability have been identified and analysed. Key steps of data preparation, data transformation, and data analytics techniques have been discussed; existing machine learning algorithms and methods described in the literature have been categorised, summarised, and compared. Finally, what techniques were lacking or under-addressed in the existing research has been elaborated with the purpose of pinpointing future research directions.  相似文献   
2.
The crystal structure of the complex between oligonucleotide containing the bacterial ribosomal decoding site (A site) and the synthetic paromomycin analogue 1, which contains the gamma-amino-alpha-hydroxybutyryl (L-haba) group at position N1 of ring II (2-DOS ring), and an ether chain with an O-phenethylaminoethyl group at position C2' of ring III, is reported. Interestingly, next to the paromomycin analogue 1 specifically bound to the A site, a second molecule of 1 with a different conformation is observed at the crystal packing interface which mimics the A-minor interaction between two bulged-out adenines from the A site and the codon-anticodon stem of the mRNA-tRNA complex. Improved antibacterial activity supports the conclusion that analogue 1 might affect protein synthesis on the ribosome in two different ways: 1) specific binding to the A site forces maintenance of the "on" state with two bulged out adenines, and 2) a new binding mode of 1 to an A-minor motif which stabilizes complex formation between the ribosome and the mRNA-tRNA complex regardless of whether the codon-anticodon stem is of the cognate or near-cognate type.  相似文献   
3.
This paper analyses two queueing models consisting of two units I and II connected in series, separated by a finite buffer of size N. In both models, unit I has only one exponential server capable of serving customers one at a time and unit II consist of c parallel exponential servers, each of them serving customers in groups according to general bulk service rules. When the queue length in front of unit II is less than the minimum of batch size, the free servers take a vacation. On return from vacation, if the queue length is less than the minimum, they leave for another vacation in the first model, whereas in the second model they wait in the system until they get the minimum number of customers and then start servicing. The steady-state probability vector of the number of customers waiting and receiving service in unit I and waiting in the buffer is obtained for both the models, using the modified matrix geometric method. Numerical results are also presented.  相似文献   
4.
The experimental study presented in this paper explores the distribution of the mean velocities for a channel receiving spatially varied (SV) inflow from directly above the centerline of the channel via sets of nozzles. The velocity components u, v, and w have been measured using a laser Doppler velocimeter. Initially the validity of the law of the wall in the channel receiving SV inflow was investigated. It was found that the measured velocity profile within the inertial sublayer region near the channel bed falls below the line representing the log law. Further, if the SV inflow enters at the center of the channel, the degree that the data depart from the log law increases from the sidewall toward the center of the channel. The structures of the velocity distributions are also presented in detail. The results include both near field, that is the area close to where the flow enters the channel, and far field measurements. It was found that the influence of the SV inflow on velocity profiles is largely contained within the SV inflow zone and that the influence within this zone reduces in the downstream direction. At any one section within this zone the influence reduces from the center of the channel toward the sidewall. In addition, some features of the secondary flow established by the SV inflow are described.  相似文献   
5.
WO3 films were deposited on glass substrates using radio frequency magnetron sputtering in a mixed gas of 80%Ar-20%O2. From the X-ray diffraction patterns, the WO3 films deposited at source to substrate distance (DT-S) of 40 mm were polycrystalline, crystallizing in the monoclinic crystal structure, with highly preferred c-axis orientation perpendicular to the film plane. On the other hand, amorphous films were observed in the WO3 films deposited at 70 mm. The crystallite sizes of the WO3 films deposited at DT-S of 40 mm were larger for films deposited at lower working gas pressures (PW). The optical absorption edge of the films shifted to shorter wavelength region with increase in PW irrespective of the DT-S. The oxygen deficient films are obtained when the films are deposited at DT-S of 40 mm and PW of 0.3 Pa and stoichiometric films are formed at higher PW. The photocatalytic oxidation of methanol proceeds via CO and formaldehyde as the intermediate species on WO3/TiO2 bilayer films and CO2 is identified as the final product.  相似文献   
6.
Urban stormwater runoff, which consists of inorganic and organic contaminants, is a major source of pollutants to receiving waters and therefore they need to be removed. Simultaneous removal of contaminants, Cd2+, Cu2+, Ni2+, Zn2+ (heavy metal cations), and SeO42− (oxyanion) from a simulated stormwater by a hydrous ferric oxide (HFO) was studied in batch and column sorption experiments. In the batch experiment the rate of sorption of the ions was rapid at the beginning and reached equilibrium in approximately 300 min. The amounts of ions sorbed were proportionate to the respective initial concentration of the ions added to the HFO. Cluster analysis showed that all heavy metals had similar sorption behavior, whereas Se had a distinctly different sorption process. Of the three different kinetic models tested the pseudo-first order kinetic model fitted the data the best. The column experimental results beyond 180 min were consistent with those of the batch experiment that the removal efficiencies of the ions were in proportion to the ion concentration in the feed. Below 180 min, Cu appeared to be preferentially removed than Zn.  相似文献   
7.
Dye-sensitized solar cells (DSCs) have been put forward as a potential low-cost alternative to the widely used silicon solar cells, which are subject to cost limitations. However, some problems need to be solved in order to enhance the efficiency of DSCs. In particular, the electron recombination occurred by the contact between the transparent conductive oxide (TCO) and a redox electrolyte is one of the main limiting factors of efficiency. Accordingly, a compact layer plays an important role in realizing highly efficient DSCs because it improves the adhesion of the TiO2 to the TCO and provides a larger contact area and more effective electron transfer by preventing electron recombination. In this work, the fabrication of a TiO2 compact layer using Ti sputter deposition and acid-treatment was investigated rather than the conventional method, which uses a TiCl4 aqueous solution. The acid-treatment of the sputtered Ti film actively oxidized the Ti particles. As a result, such a cell exhibited an additional 1.3% in total efficiency compared to the standard DSC without a compact layer. These improvements are not inferior to those obtained by the conventional fabrication method using a TiCl4 aqueous solution.  相似文献   
8.
Road traffic congestion is a serious problem in today's world and it happens because of urbanization and population growth. The traffic reduces the transport efficiency in the city, increases the waiting time and travel time, and also increases the usage of fuel and air pollution. To overcome these issues this papers propose an intelligent traffic control system using the Internet of Vehicles (IoV). The vehicles or nodes present in the IoV can communicate between themselves. This technique helps in determining the traffic intensity and the best route to reach the destination. The area of study used in this paper is Vellore city in Tamilnadu, India. The city map is separated into many segments of equal size and Ant Colony Algorithm (AOC) is applied to the separated maps to find the optimal route to reach the destination. Further, Support Vector Machine (SVM) is used to calculate the traffic density and to model the heavy traffic. The proposed algorithm performs better in finding the optimal route when compared to that of the existing path selection algorithms. From the results, it is evident that the proposed IoV‐based route selection method provides better performance.  相似文献   
9.
Crystalline water-free β-phase Ca0.14V2O5 is reported for the first time as a viable cathode material for calcium-ion batteries (CIBs). In contrast to layered α-V2O5 and δ-CaxV2O5·nH2O, which have limited capacity, the β-phase delivers a reversible capacity of ≈247 mAh g−1, which corresponds to the insertion/extraction of Ca2+ between Ca0.14V2O5 and Ca1.0V2O5. The process of Ca2+ insertion process and the accompanying structural relaxation are theoretically and experimentally verified. The initial insertion of Ca2+ into Ca0.14V2O5 causes a slight shift of oxygen atoms surrounding hepta-coordination sites, creating penta-coordinated sites that are then partially filled up to Ca0.33V2O5. Further insertion occurs through the stepwise occupation of up to 50% of neighboring hexa- and tetra-coordination sites to form Ca0.67V2O5 and Ca1.0V2O5, respectively. The rearrangement of oxygen atoms in Ca0.14V2O5 also minimizes dimensional changes, leading to high cyclic stability during repeated charge/discharge cycles. The remarkable electrochemical performance of full cells containing a Ca0.14V2O5 cathode and a K metal anode in Ca2+/K+ hybrid electrolytes, is also demonstrated, thanks to the inertness of K+ insertion into Ca0.14V2O5 and the absence of calcium plating/stripping. The cyclic stability and high capacity of Ca0.14V2O5 is not compromised in hybrid electrolytes, making it a viable CIB cathode.  相似文献   
10.
1 经济低迷勇升级,迎接复苏好时机 当前的经济形势将对企业形成压力,促使其降低成本。本能反应当然是对无直接效益的业务实施成本削减战略,IT一类当然成了“矛头所指”。然而,正当人们谈论缩减规模之时,IT投资实际上却可以实现切实可见的商业效益。为节省成本而三思熟虑的策略未必有效,长远来看,这种做法甚至可能适得其反。  相似文献   
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