nils-herrmann/clean_scirepeval huggingface dataset:
A Study on AC Losses of HTS Pentagonal Conductors Consisting of 2G Wires Carrying DC Offset Transport Current

In a high-voltage dc (HVDC) transmission system, a high-temperature superconducting (HTS) dc cable is a feasible candidate due to its high power density. However, the dc in the grid includes ac ripple generated from switching devices and the environment, which can cause ac losses. In this paper, two pentagonal conductors consisting of second-generation (2G) wires are prepared, and their ac losses are investigated under the application of current with ac and dc components. Moreover, a numerical analysis is performed for both conductors to compare the measured losses. The results show that the measured ac losses correspond well with the numerical ones calculated by our models. The dc offset current does not affect the ac losses when the total current is smaller than the critical current, and the ac losses depend on the amplitude of the ac component. All measured losses are verified by evaluating the dependence on the arrangement of the voltage leads, the contact position, and the frequency.
Study on fault phase selection based on FFT and phase-separation current phase difference of high-voltage transmission lines

The phase relationship of each phase on both sides of the short circuit point of the high-voltage transmission lines is analyzed in all kinds of fault conditions, and a reliable fault phase selection method based on phase-separation current phase is presented. In the fault phase selection process, the fault current component of each phase is computed first, and the phase difference is calculated by Fast Fourier Transform (abbreviation for FFT). Then the fault type is identified according to the fault current phase difference and the existence of the zero sequence current. Finally, the different fault conditions are verified by simulation, and the results indicate that the fault phase selection method presented in this paper is effective and feasible.
A classification method of Vietnamese news events based on maximum entropy model

Based on the characteristics of Vietnamese news texts and selection of Vietnamese words and phrases, part of speech, named entities, news titles, keywords and so on, this paper proposes a classification method of Vietnamese news events based on the maximum entropy model. This method selects the named entities and news keywords in Vietnamese news titles and the event trigger words in the key sentences corresponding to the keywords as the news classification features, and adopts the maximum entropy model to achieve classification. Furthermore, this paper collects more than 6000 Vietnamese news texts, which are marked into seven kinds of news event corpora such as politics, economy and culture, etc. and subject to training, and then obtains classification model of Vietnamese news texts and achieves type classification of Vietnamese news events. The experimental results show that the accuracy of the classification method of Vietnamese news events proposed in this paper reaches 96.97%.
Finite-state Markov modeling of tunnel channels in communication-based train control (CBTC) systems

Communication-based train control (CBTC) is gradually adopted in urban rail transit systems, as it can significantly enhance railway network efficiency, safety and capacity. Since CBTC systems are mostly deployed in underground tunnels and trains move in high speed, building a train-ground wireless communication system for CBTC is a challenging task. Modeling the tunnel channels is very important to design and evaluate the performance of CBTC systems. Most of existing works on channel modeling do not consider the unique characteristics in CBTC systems, such as high mobility speed, deterministic moving direction, and accurate train location information. In this paper, we develop a finite state Markov channel (FSMC) model for tunnel channels in CBTC systems. The proposed FSMC model is based on real field CBTC channel measurements obtained from a business operating subway line. Unlike most existing channel models, which are not related to specific locations, the proposed FSMC channel model takes train locations into account to have a more accurate channel model. The distance between the transmitter and the receiver is divided into intervals, and an FSMC model is applied in each interval. The accuracy of the proposed FSMC model is illustrated by the simulation results generated from the model and the real field measurement results.
Research on 3GPP LTE Security Architecture

With the improvement and maturity of 3G network, the wireless communication rate for the users has become more and more high. Every research institution will focus gradually shift to long term evolution Version (LTE) of 3G network. In this paper, 3GPP LTE security mechanisms are introduced in detailed; the security architecture of LTE/SAE is present; the key structure and domain security of the network are studied respectively.
A novel simple electrospinning process for preparing co-axial ultrafine fibers

A novel simple electrospinning process for preparing co-axial ultrafine fibers has been successfully developed in the present paper. The electrospinning has two characteristics: (1) a co-axial spinning head was prepared from stainless steel; (2) a two-syringe infusion pump was used for driving both the core spinning medium and the shell spinning liquid synchronously. The process has good capability of fabricating co-axial ultrafine fibers. Two examples of application were conducted. The results from one experiment exhibited that composite fibers loaded with active pharmaceutical ingredient for therapeutic effects coluld be easily prepared using the one-step manufacturing process. The results from another experiment showed that ultrafine hollow fibers were able to fabricate with the polymer solutions as the shell spinning liquids and the gas CO2 as the core medium. The developed process might find applications in preparing ultrafine fibers with micro-structural characteristics and local component variations for drug delivery, separation and extractions, tissue engineering.
Research on improved Apriori algorithm based on MapReduce and HBase

In order to improve the efficiency of Apriori algorithm for mining frequent item sets, MH-Apriori algorithm was designed for big data to address the poor efficiency problem. MH-Apriori takes advantages of MapReduce and HBase together to optimize Apriori algorithm. Compared with the improved Apriori algorithm simply based on MapReduce framework, timestamp of HBase is utilized in this algorithm to avoid generating a large number of key/value pairs. It saves the pattern matching time and scans the database only once. Also, to obtain transaction marks automatically, transaction mark column is added to set list for computing support numbers. MH-Apriori was executed on Hadoop platform. The experimental results show that MH-Apriori has higher efficiency and scalability.
A Modified Feature Points Extraction Algorithm and it's Adaptability Evaluation

Extracting integral feature points is important to object recognition and 3D reconstruction in image processing field. This paper modifies a kind of feature extracting algorithm based on image edge. First, image edge contour is extracted. Second, geometric gravity center of edge outline is calculated. Third, argument-polar radius curve of polar coordinate system whose pole is geometric gravity is formed, and maximum and minimum value points are searched, they are feature points. Comparing the original algorithm, the modified algorithm can not only extract protruding points, but also concave points. In order to evaluate the quality of the algorithm, the paper appraises the adaptability of the algorithm in the case of scale transformation, rotation transformation and affine transformation. The result indicates that the algorithm is simple and its adaptability can reach 79.1%. In actual application, the algorithm has important value to auto-input of two-dimension curve based on feature points and three-dimension reconstruction.
Feasibility Study of Closed-Loop No-Insulation Coil to Shield Alternating Magnetic Field

No-insulation (NI) coil made of 2G high-temperature superconductor tape is widely used in a dc magnet due to its excellent performance of engineering current density, thermal stability, and mechanical strength. While the charging/discharging delay of the NI coil has become the biggest obstacle to applying it into an ac power device. In this paper, as a preliminary study, we test the capability of the NI coil to shield alternating magnetic field (AMF). When shielding AMF, the NI coil works in inductive mode such that each turn in the NI coil is induced at the same time and there might no longer exist any delay caused by turn-to-turn current path. To verify this hypothesis, three closed-loop coils, two NI coils, and an insulated (INS) coil are fabricated. The result of the contrast experiments shows that the NI coil could shield all the alternating magnetic flux through it, independent of turn-to-turn resistance and frequency of the background AMF. This capability is promising for the NI coil to be applied in the inductive superconducting fault current limiter (iSFCL) as the secondary winding, which can shield all the magnetic flux generated by the primary winding to keep the impedance of the iSFCL at a very low level during normal the operation of the power system.
Triple-Band Cavity Bandpass Filters

This paper presents a new class of cavity-based triple-band filters employing resonators that support three operation modes. The proposed triple-band filters do not require junctions and can achieve an equivalent Chebyshev performance with fewer cavities, thus significantly reducing the footprint when compared to traditional approaches. The filter facilitates a systematic design approach starting from the coupling-matrix generation to the overall response optimization. The concept is potentially applicable to most triple-mode resonators and is demonstrated in this paper using waveguide and dielectric resonators. The first design is an inline structure employing elliptical waveguide cavities, whereas the second design is a folded structure using rectangular waveguide cavities. The third design is implemented by dielectric loaded cavity resonators. All the proposed triple-band filter designs offer high Q and allow for independent control of each frequency and coupling parameter. To verify the concept, three triple-band filter examples with different realizations are designed, manufactured, and tested to allow comparisons.
Study on the Time-Dependent Orienteering Problem

In the orienteering problem (OP) a set of locations is given, each with a score. The goal is to determine a route, limited in length, that visits some locations and maximize the sum of the collected scores. The orienteering problem is often used as a starting point for modeling many combinatorial optimization problems. This paper studies the time-dependent orienteering problem taking into account the travel cost varying with time and stay time constraints. After a mixed integer programming model is proposed, a novel optimal pre-node labeling algorithm is designed based on the idea of network planning and dynamic programming. Finally, a numerical example is presented to show the validity and feasibility of this algorithm.
Application of multi-agent and data mining techniques in condition assessment of transformers

The framework of the assessment system for transformer condition is proposed using data warehouse, multi-agent system and data mining technologies synthetically. It is used to support the condition-based maintenance of transformer, improve the equipment reliability and reduce the substation operation cost. The health state of the transformer depends on the design, present and historical operation conditions of equipment. Usually, the off-line testing results, operation history and fault records of equipment, and weather conditions, etc. have been stored in different systems and they are very difficult to be utilized synthetically. Therefore, a data warehouse has been set up to integrate all of these data. We used data mining techniques to get the regulation and trend of the health condition of transformer and then make a conclusion. In order to implement the system efficiently and effectively, we employed some ideas of open agent architecture (OAA) to compose a multi-agent-based framework of the proposed system.
ESD prevention on an unshunted MR head

A magneto-resistive (MR) head is easily damaged by a transient current due to electrostatic discharge (ESD). Often the current is introduced through unshunted leads. The damage can be prevented by two practical methods. First, the potential of a MR head and any bare conductor can be equalized through a large resistor before direct contact. Second, the MR head potential can be reduced capacitively, i.e. through a virtual ground. Several examples are described.
Study on the Drink Driving Behavior of Drivers in Beijing Based on the Theory of Plan Behavior

Rapid development of the Intelligent Transportation Systems (ITS) has greatly increased the traffic safety. In order to improving the safety status caused by drink driving in China, a questionnaire study was conducted with drink driving behaviors in Beijing to help understand the attitude, subjective norm, perceive behavioral control and intentions of drink driving in Beijing using the theory of planned behavior (TPB). The direct and indirect factors involved in self-reported drink driving behaviors are examined. Perceived behavioral control appears to be the best direct predictor of self-reported drink driving behavior. Subjective norms and intentions have weaker direct links with drink driving behavior. Past drink driving experience is the obvious factor which greatly effects the attitudes, subjective norms, perceive behavioral control and intentions of the drink driving. Subsequently, some advice on the development of ITS technology and products for drink driving behavior is suggested.
A Bipolar-Pulse Voltage Method for Junction Temperature Measurement of Alternating Current Light-Emitting Diodes

We introduce a new method for measuring the junction temperature of alternating current light-emitting diodes. This method employs a periodic bipolar voltage pulse signal as the input, and utilizes the amplitude of corresponding output current as the temperature sensitive parameter (TSP), of which a linear temperature dependence is proven in a prior experiment in this paper. On the basis of the TSP, we devise a detailed procedure—first, measure the thermal resistance of the package of ac-LEDs, which further contributes to the calculation of junction temperatures under various power inputs. Comparisons between values calculated by using this method and those obtained directly from a thermocouple indicate a decent accuracy of the former. The advantage of this method benefits from the stability of thermal resistance under different driving conditions that one could immediately obtain the junction temperature by measuring the electric and optical powers.
Handoff Performance Improvements in MIMO-Enabled Communication-Based Train Control Systems

Communication-based train control (CBTC) is an automated control system for railways using data communications. CBTC systems have stringent communication latency requirements. For rail transit systems, wireless local area network (WLAN)-based CBTC is a popular approach due to the wide availability of commercial-off-the-shelf WLAN equipment. However, WLANs were not originally designed for high-speed environments with frequent handoffs, which may result in communication interrupt and long latency. In this paper, we propose a handoff scheme in CBTC systems based on WLANs with multiple-input-multiple-output (MIMO) technologies to improve the handoff latency performance. In particular, we consider channel estimation errors and the tradeoff between MIMO multiplexing gain and diversity gain in making handoff decisions. The handoff problem is formulated as a partially observable Markov decision process (POMDP), and the optimal handoff policy can be derived to minimize the handoff latency. Simulations results based on real field channel measurements are presented to show the effectiveness of the proposed scheme.
Influence of Transport Mode on AC Loss Characteristics of a Bi-2223 Tape in a Multi-Tape Conductor

The high-temperature superconductor (HTS) with large current capacity has been developed for power applications such as power transmission cables and fault current limiters. Especially, in these power applications, AC loss is very important in an economic point of view but this issue has not been completely elucidated due to its many complexities. In this work, two HTS conductors with very different critical current densities, which consist of several Bi-2223 tapes placed on a cylindrical former, were fabricated in an attempt to arrive at a clear understanding of their AC loss characteristics. AC loss characteristics for such two cylindrical multi-tape conductors have been experimentally investigated. Moreover, the influence of current transport mode on the AC loss of the Bi-2223 tape in the conductors was investigated. DC voltage-current characteristics of the Bi-2223 tapes were also measured for discussions on the measured AC losses. The results show that for the conductor with high critical current density, the measured AC loss strongly depends on the transport mode as in the conductor with low critical current density. However, the transport mode dependence of the conductor with high critical current density becomes weaker and weaker as transport current increases. In the simultaneous mode, the measured AC loss of the conductor with low critical current density is in good agreement with the calculated loss from the monoblock model. However, the measured loss of the conductor with high critical current density does not coincide with both the numerically calculated loss and loss calculated from the monoblock mode.
Comparison of alternate analytical models for predicting cogging torque in surface-mounted permanent magnet machines

Permanent magnet brushless machines exhibit high efficiency and torque density, and have already been employed in hybrid electric vehicles. However, one of their disadvantages is the inherent cogging torque, which is a kind of torque ripple and always desirable to minimize. Six analytical models for cogging torque prediction are presented and compared in this paper. These analytical models are progressively refined and differ in methods for calculating the permeance due to stator slotting (i.e. with/without considering the slot leakage), the airgap field distribution due to permanent magnets (i.e. with/without considering the inter-pole leakage and/or curvature effect), and the cogging torque (based on the energy method or the net lateral force acting on the stator teeth). Developed analytical models are used to predict the cogging torque waveforms, the optimal magnet pole-arc to pole-pitch ratio and the optimal slot opening in three machines having different combinations of slot number and pole number, viz. 18/24, 9/8, and 24/16, respectively, and are extensively validated by the finite element analyses. It shows that accounting for the slot leakage and/or magnet interpole leakage can significantly improve the accuracy of cogging torque prediction, while the method for predicting the cogging torque based on the calculation of net lateral force acting on the stator teeth exhibits a higher accuracy than that based on the energy method.
Modeling and Identification of Piezoelectric-Actuated Stages Cascading Hysteresis Nonlinearity With Linear Dynamics

In this paper, we propose a new modeling and identification approach for piezoelectric-actuated stages cascading hysteresis nonlinearity with linear dynamics, which is described as a Hammerstein-like structure. In the proposed approach, the hysteresis and linear dynamics together with the delay time and higher order dynamic behaviors are obtained with three data-driven identification steps under designed input signals. In the first step, the step input signal is applied to estimate the delay time of the piezoelectric-actuated stages. In the second step, the autoregression with exogenous signal identification algorithm is adopted to identify the linear dynamics using a small-amplitude band-limited white noise input signal. In the third step, with the identified linear dynamics model, the parameters of the rate-independent Prandtl-Ishlinskii hysteresis model are identified by the particle swarm optimization algorithm using a simple low-frequency triangle input signal with different amplitudes. Finally, the experimental results on a piezoelectric-actuated stage show that both the hysteresis and dynamic behaviors of the piezoelectric-actuated stage are well predicted by the proposed modeling method. In addition, we provide the analysis of quantitative prediction errors of the identified model with comparison to experimental data, which clearly demonstrate the effectiveness of the proposed approach.
PNG File Decoding Optimization Based Embedded System

Portable Network Graphics (PNG) is a bitmapped image format that employs lossless data compression. PNG is created to improve upon and replace GIF (Graphics Interchange Format) as an image-file format not requiring a patent license. The PNG file is widely used in embedded systems. In this paper, the PNG file structure and decoding process is introduced. According the PNG data chunks, the decoding optimization methods are proposed. Experiments show that the optimization methods can significantly improve the efficiency and reduce the file size.
ROME: Rateless Online MDS Code for Wireless Data Broadcasting

Packet level coding schemes are used to improve the transmission reliability and efficiency in data broadcasting applications, especially for wireless networks. However, existing coding schemes have large redundancy for packets are coded by a random way or some certain probability distributions. Although the Maximum Distance Separable (MDS) codes are designed without redundancy, they are not effective when the packet erasure probability is high. To reduce the coding redundancy, lots of work use the receiver side information to adjust the codes construction on-the-fly, which is more beneficial. However, these work have disadvantages:1) the coding redundancy is also large; 2) the feedback schemes have great affect on performance. In this paper, we design a robust feedback scheme and a novel "Rateless Online MDS Code"(ROME) to eliminate the coding redundancy. Our contributions include that our codes are throughput optimal codes without redundancy, and the analysis on theoretical finite field size bound to achieve throughput optimal codes. We also design the finite field construction to speed up the encoding and decoding process. Finally, we compare the performance between ROME and other existing codes, like RLC, LT, RT oblivious and SLT codes, and their performance when feedbacks are erased.