Search

Car ferry services constitute an important part of the transportation network in several parts of the world, especially in areas with limited alternative modes of transport. A central problem facing decision makers is the socially optimal capacity of ferry services. However, the literature has not examined all the decision variables the are relevant to decision makers in a simultaneous framework, only partially. We add to the literature by treating all the relevant decisions variables in a simultaneous framework, which enables a more complete representation of optimal capacity, than partial frameworks. Our proposed methodology also includes the cost of not being able to board the first arriving departure, which is an essential cost in the case of car ferries with too low capacity. We apply the methodology to a case study of three major ferry crossings in Norway. Results indicate that a too large capacity is provided. Thus, local policy makers should consider revising the current service levels. Other policy makers may enact better decisions based on the findings we provide. Sensitivity test suggests that the method used to estimate the number of users not being able to board due to capacity concerns may be improved. This, however, does not alter our main conclusion.

On one hand, large-scale ranking and selection (R&S) problems require a large amount of computation. On the other hand, parallel computing environments that provide a large capacity for computation are becoming prevalent today, and they are accessible by ordinary users. Therefore, solving large-scale R&S problems in parallel computing environments has emerged as an important research topic in recent years. However, directly implementing traditional stagewise procedures and fully sequential procedures in parallel computing environments may encounter problems because either the procedures require too many simulation observations or the procedures’ selection structures induce too many comparisons and too frequent communications among the processors. In this paper, inspired by the knockout-tournament arrangement of tennis Grand Slam tournaments, we develop new R&S procedures to solve large-scale problems in parallel computing environments. We show that no matter whether the variances of the alternatives are known or not, our procedures can theoretically achieve the lowest growth rate on the expected total sample size with respect to the number of alternatives and thus, are optimal in rate. Moreover, common random numbers can be easily adopted in our procedures to further reduce the total sample size. Meanwhile, the comparison time in our procedures is negligible compared with the simulation time, and our procedures barely request for communications among the processors.

Aiming at solving the problems of bad imperceptibility and low embedding rate of existing algorithms, a novel large-capacity reversible image watermarking based on improved difference expansion (DE) is proposed. Firstly, the smoothness calculation algorithm is used to calculate and sort the smoothness values of the divided image sub-blocks; then, the scrambled watermark is embedded into the sub-blocks with less smoothness after removing the abrupt point by using the generalized difference expansion (GDE); finally, the absolute difference operation is applied to the generated overflow pixels to make their pixel values within a reasonable range for embedding watermark information. Under the premise of ensuring a certain visual quality, multiple watermark embedding can effectively improve the embedding rate. The simulation results show that this algorithm not only realizes blind extraction, but also recovers the original images without loss. At the same time, this algorithm achieves a high embedding rate (the average embedding rate is as high as 77.91 dB) without decreasing the visual quality.

A recent ultra-large SSD (e.g., a 32-TB SSD) provides many benefits in building cost-efficient enterprise storage systems. Owing to its large capacity, however, when such SSDs fail in a RAID storage system, a long rebuild overhead is inevitable for RAID reconstruction that requires a huge amount of data copies among SSDs. Motivated by modern SSD failure characteristics, we propose a new recovery scheme, called reparo , for a RAID storage system with ultra-large SSDs. Unlike existing RAID recovery schemes, reparo repairs a failed SSD at the NAND die granularity without replacing it with a new SSD, thus avoiding most of the inter-SSD data copies during a RAID recovery step. When a NAND die of an SSD fails, reparo exploits a multi-core processor of the SSD controller in identifying failed LBAs from the failed NAND die and recovering data from the failed LBAs. Furthermore, reparo ensures no negative post-recovery impact on the performance and lifetime of the repaired SSD. Experimental results using 32-TB enterprise SSDs show that reparo can recover from a NAND die failure about 57 times faster than the existing rebuild method while little degradation on the SSD performance and lifetime is observed after recovery.

To accommodate the ever-increasing wireless capacity, the terahertz (THz) orbital angular momentum (OAM) beam that combines THz radiation and OAM technologies has attracted much attention recently, with contributing efforts to explore new dimensions in the THz region. In this paper, we provide an overview of the generation and detection techniques of THz-OAM beams, as well as their applications in communications. The principle and research status of typical generation and detection methods are surveyed, and the advantages and disadvantages of each method are summarized from a viewpoint of wireless communication. It is shown that developing novel THz components in generating, detecting and (de)multiplexing THz-OAM beams has become the key engine to drive this direction forward. Anyway, beneficial from the combination of infinite orthogonal modes and large bandwidth, THz-OAM beams will have great potential in delivering very large capacity in next generation wireless communications.

Задачі підсуNowadays with the rapid development of information technologies, UAV-based Remote Sensing (drone remote sensing) gives a new opportunities for conducting scientific research in a much more detail way. UAVs (unmanned aerial vehicles) give the opportunity to acquire data at sufficiently low cost. They also provide remote data more rapidly than piloted aerial vehicles. Nowadays drones are often used, because application of piloted aerial vehicles can be dangerous, difficult and expensive for some territories. Application of low altitude UAVs give a possibility to achieve images with a very high resolution and sufficient precision. In this article structure and main details of drones were considered. It also was noted, that technologies of UAV-based Remote Sensing are used in different areas.Agricultural drones help to analyze crops, make decisions on how to use the crop information and take the necessary actions to correct the problems. These unmanned aerial vehicles let to see fields from the sky. Agricultural drones are used to help increase crop production and monitor crop growth. Drones and sensors give a detail picture of fields. They can survey the fields periodically. Agricultural drones can reveal many issues such as soil variation, pest infestations and changes in the crops over time. They also show differences between healthy and unhealthy plants. Drones are flied over the crops and help to make decisions on how to proceed given the crop information. Nowadays there is a large capacity for growth in the area of agricultural unmanned aerial vehicles. With technology constantly improving, imaging of the crops will need to improve as well.Drones are used for exploring for minerals and mapping deposit sites, they are used in the oil and gas industry for remote monitoring. Drones can provide information of nature disasters and give help to assess property damage. They help to conduct forest monitoring and to assess plant health. Unmanned aerial vehicles are also used in a military capacity and ecological monitoring. It also was noted, that there is a large capacity for development and improvement of unmanned aerial vehicles.путникового моніторингу в аерокосмічному комплексі

This work presents an assessment of the applicability of existing benchmark critical experiments to the criticality safety code validation for a large-capacity high-assay low-enriched uranium (HALE...

As emergencies occur more frequently, such as natural disasters and industrial accidents, evacuation planning attracts more and more attention. Bus is often used to evacuate car-free people due to its large capacity and manageability. To improve the efficiency and practicality of public transport evacuation plans, this paper presents a round-trip bus evacuation model based on unfixed routes with simultaneous optimization of bus scheduling and routing planning. With constraints of bus capacity, evacuee demand at pick-up points, time windows and flow balance, the proposed model aims to reduce the total evacuee time cost, including in-bus travel time and waiting time. Moreover, a two-layer algorithm, integrating the insertion algorithm and the edge-exchange algorithm, is devised to obtain the model sub-optimal solution. To verify the effectiveness of the proposed model and solution, two cases are presented in this paper. In the first case, the proposed model and algorithm manage to solve bus evacuation problems effectively. Furthermore, sensitivity analyses are conducted to show the impact factors on the objective function. Based on the realistic topology and size network of Ningbo in China, the second case illustrates the practical value of the model and solution in large-scale evacuation, and demonstrates the superiority over the conventional solution.

Orbital angular momentum (OAM) transmission is expected to be implemented for large capacity communication. However, the beam divergence brings severe difficulties for the long-distance transmission especially in the radio frequency (RF). As a promising solution, a distributed antennas scheme for OAM long-distance reception is highlighted in this letter. In order to realize synchronization and offsets compensation between different receiving signals, a distributed compensation network with its feedback links is also proposed and illustrated. Specifically, a novel frame format is designed for the multiplexed OAM signals. The experiments show that this scheme can effectively separate multiple OAM signals and reduce the crosstalk between different channels, which leads to a good experimental bit error rate (BER) with acceptable links overhead. The proposed design is expected to be the promising applications in the future wireless communications such as the fronthauls and the backhauls.

PT PLN (PERSERO) is a company engaged in electricity in Indonesia and plays a role in the generation and distribution of electricity to consumers. PLN has quality standards that must be met, one of which is a stable frequency even though the load keeps changing all the time. In electric power systems, the frequency value is an indicator of the balance between active power generated with a total load of active system power and losses. The frequency value will increase if there is an excess generation and conversely the frequency value will decrease if there is a shortage of generation or overload. If there is a disturbance that causes the large capacity generating unit to be release from the systems (trip), in this case the PLTU Pangkalan Susu and PLTU Nagan Raya will cause a decrease in frequency so that the Northern Sumatera interconnection system is disrupted. A large decrease in frequency can lead to failure of generating units in a row so that it can cause total system failure (blackout). To avoid a total system failure (blackout) a load shedding scheme with under frequency relay (UFR) is carried out. This research is done by experimental methods. According to this research, it’s been found that the setting of under frequency relay conducted by PLN UP2B Northern Sumatera is good, in this sense of blocking the system from blackout due to a massive power trip.

In recent years, the introduction of energy storage batteries has gained in importance from the viewpoint of the stabilization of electric power systems, with global promotion for the introduction of renewable energy sources. Redox flow batteries (RFBs) offer excellent features, including suitability to large capacity, a long lifetime, and a high level of safety. It has already been 40 years since its basic principle was proposed by NASA in 1974. At present, RFBs adopting vanadium (V) electrolytes have been aggressively developed and operated in various parts of the world. Hokkaido Electric Power Company in Japan has started practical operation of a RFB system with a capacity of 15 MW × 4 h. This review will describe development trends and some operation case examples from the viewpoint of RFB systems.

In-memory computing has inspired researchers to consider integrating large-capacity persistent memory (PM) into the main memory subsystem. However, several challenges still remain for providing an integration approach for DRAM-comparable PM on existing enterprise servers. Current commercial servers tend to feature multiple sockets with shared-memory NUMA organizations. Simply constructing a hybrid main memory architecture for these NUMA organizations requires considerable modifications of the system software. Another significant problem in these designs is the high latency of accessing PM on a remote socket, which results in performance degradation. To address these problems, we integrated PM as a memory-based model and as a storage-based model simultaneously on one commercial server, which offers a short-cut approach for enterprises to build commercial NUMA machines with large-capacity PM. In the memory-based model, rather than focusing on the persistence attribute, we propose an architecture that benefits managing the integrated PM and DRAM space in a unified manner and that facilitates bypassing vast modifications to the system software. We also present an adaptive mechanism that can automatically introduce a moderate amount of PM into the local socket to hinder access of a remote socket by the degree of memory pressure. In the storage-based model, under the condition of taking full advantage of the PM's persistence, we abstract a PM volume device and overcome the torn sector problem. To demonstrate the effectiveness of the proposed scheme, we design and implement Dapper, an adaptive persistent memory manager prototype. The experimental results show that, compared to typical memory management approaches, Dapper achieves performance improvements of 13.1 percent to 34.0 percent on average on Graph500 BFS_SSSP benchmarks and SPEC CPU2006 floating point workloads, respectively. Moreover, when deploying F2FS on our PM volume, we find that Dapper outperforms existing methods by 5.8 percent on tar and by 11.9 percent on untar.

In previous data hiding techniques, binary rules are usually used to guide the fine-tuning of the values of basic objects in the host media to hide bit 0 and bit 1. In this paper, we propose a new data hiding technique for gray images based on querying a 256x256 information table. The information table is constructed by cloning a 3x3 basic block, which we call seed block. Eight unsigned integer values between 0 and 7, i.e., 3 bit binary data, are assigned to different elements of the seed block. Each time, a pair of pixels are chosen from a host image, and their pixel values are used as row and column numbers to look up the information table. If element value obtained by looking up the table is equal to the 3 bit binary data to be hidden, the values of the pixel pair will remain unchanged. Otherwise, take this element as the central point, we call it the focus element, to enclose a 3x3 window in the information table. Then in the window, find the element which is equal to the data to be hidden. Finally, update the pixel values of the pair with the row and column numbers of the found element in the window. Since the row and column numbers are in the range of 0-255, the updated pixel values will not overflow. In the proposed algorithm, a pair of pixels can hide 3 bits of information, so the embedding capacity is very high. Since the adjustment of pixel values is constrained in a 3x3 window, the modification amount of pixel values is small. The proposed technique belongs to fragile digital watermarking, so it can be used for image authentication and tamper localization. By the evaluation of data hiding capacity, security, imperceptibility, computational cost and extensibility, this algorithm is superior to existing information hiding techniques. The proposed technique can also be used in color image and audio data hiding.

High-Speed Railway(HSR), due to its advantages of high-velocity, large capacity, punctuality, et al., developed rapidly in recent years, forming a networked operation scale. The connectivity status for different Origin-Destination(OD) pairs varied with time according to train timetables. To reveal the dynamic characteristics of the HSR network resulted from the changing connection status of OD pairs, this paper proposed an HSR Spatio-temporal Network(SN) model to analyze the dynamic characteristics of the HSR network. Then the spatiotemporal characteristic path length and the spatio-temporal betweenness centrality are studied by transforming the SN network into a Spatio-temporal Nodes based Network(SNN). Moreover, an indicator named spatio-temporal connectivity is proposed to derive the connectivity status variation of the HSR. Cases study reveal the quantitative relationship between the train timetable and the transportation performance and the evolution law of the network characteristics. The results could be used further to optimize the organization of trains from a network perspective.

Despite the continuous downscaling of complementary metal–oxide–semiconductor (CMOS) devices, various scenarios of technology have also been proposed toward the shrinking of semiconductor memory. In this paper, a high-density memory (HDM) has been proposed on the basis of band-to-band tunneling (BTBT) for low-power, high density, and high-speed memory applications. The geometric structure and electrical properties have been demonstrated by using TCAD tools. Typical memory operations including read, program, and erase have been designed and performed. High operation speed, lower power consumption, as well as good reliability characteristics have been achieved by simulation, which indicates that the HDM may have potential application value as a novel semiconductor memory device.

In open-plan office rooms, one of the main reasons for the nuisance of work is the noise from employees' conversations. In order to limit it, the permissible values of the parameters characterizing the acoustic properties in those rooms on a 2-level scale are defined.The article introduces a 3-level scale for assessing the acoustic properties (bad, fair, good) of a room based on EN ISO 3382‑3:2012 and PN-B-02151-4:2015 - criterion 1. Additionally and alternatively, a new 3-level scale assessment criterion (criterion 2), concerning acoustic separation between groups of workstations, was determined. In order to meet that criterion, it is necessary to take into account the acoustic treatment of the room. A multivariate (7) acoustic treatment studies were performed using computational simulation methods.Requirements, according to PN-B-02151-4:2015, were met after the application of a sound-absorbing suspended ceiling and acoustic screens at workplaces. To meet the requirements of EN ISO 3382‑3:2012, it was necessary to additionally use sound-absorbing materials on the walls and acoustic screens separating the naves of the room. To meet the requirements of criterion 2, it was necessary to additionally use acoustic screens separating groups of workstations and acoustic screens in passages.Appropriate acoustic properties can be obtained in open space offices. Appropriate acoustic properties can be obtained in open-space offices. The requirements according to PN-B-02151-4:2015 can be met with much lower acoustic treatment than the requirements according to EN ISO 3382‑3:2012. The use of a 3-level scale for assessing the acoustic properties of a room allows for the differentiation of rooms with regard to their acoustic properties. The introduction of a new assessment method, taking into account the grouping of workplaces in a room, makes it possible to assess the acoustic properties of a room in a more reliable way, by neglecting the impact on the assessment of areas where people are not present. Med Pr. 2021;72(4):375-90.W biurowych pomieszczeniach open space jedną z podstawowych przyczyn uciążliwości pracy jest hałas rozmów pracowników. W celu jego ograniczenia określono dopuszczalne wartości wielkości charakteryzujących właściwości akustyczne w tych pomieszczeniach w skali dwustopniowej.W artykule wprowadzono trzystopniową skalę oceny właściwości akustycznych pomieszczenia (złe, słabe, dobre) bazującą na wielkościach oceny według PN-B-02151-4:2015 oraz PN-EN ISO 3382‑3:2012 – kryterium I. Określono dodatkowo nowe, także trzystopniowe, II kryterium oceny dotyczące separacji akustycznej między grupami stanowisk pracy. W celu jego spełnienia konieczne jest uwzględnienie adaptacji akustycznej pomieszczenia. Podano wyniki badania metodami symulacji obliczeniowej wielowariantowej (7) adaptacji akustycznej w pomieszczeniu trzynawowym.Wymagania PN-B-02151-4:2015 (kryterium I) zostały spełnione po zastosowaniu: dźwiękochłonnego sufitu podwieszanego i ekranów akustycznych przy stanowiskach pracy. Do spełnienia wymagań PN-EN ISO 3382-3:2012 (kryterium I) konieczne było dodatkowe uwzględnienie materiałów dźwiękochłonnych na wewnętrznych ścianach pomieszczenia oraz ekranów akustycznych rozdzielających nawy pomieszczenia. Do spełnienia wymagań kryterium II konieczne okazało się dodatkowe zastosowanie ekranów akustycznych rozdzielających grupy stanowisk pracy oraz ekranów akustycznych w ciągach komunikacyjnych dla pieszych.Jest możliwe uzyskanie odpowiednich właściwości akustycznych w pomieszczeniach biurowych open space. Wymagania określone zgodnie z PN-B-02151-4:2015 można spełnić przy znacznie mniejszej adaptacji akustycznej niż wymagania PN-EN ISO 3382‑3:2012. Zastosowanie trzystopniowej skali oceny właściwości akustycznych pomieszczenia pozwala w bardziej precyzyjny sposób różnicować je pod względem ich właściwości akustycznych. Wprowadzenie nowego sposobu oceny, uwzględniającego grupowanie stanowisk pracy w pomieszczeniu, pozwala w bardziej miarodajny sposób oceniać właściwości akustyczne przez pominięcie wpływu na ocenę obszarów, w których nie przebiega praca. Med. Pr. 2021;72(4):375–390.

Owing to its fast response, the hydro power plant is normally assigned to provide spinning reserve for the power system. Despite of its large capacity, minimum generation constraint and lack of management of multi-unit generations result in limited spinning reserve. This paper solves this problem by integrating a battery energy storage system with the hydro power plant and proposes a unit management algorithm to cooperatively manage the multi-unit generation. As a result, the hydro power plant can virtually provide any demanded generation, and its spinning reserve is increased significantly compared to the traditional operation. A case study on Rajjaprabha hydro power plant in Thailand is conducted to confirm feasibility of the proposed concept.

In the 5th generation mobile communication system, high frequency bands over 6GHz are used to realize high speed and large capacity communication. Because of high path losses, these bands are considered to use in small cells at low base station antenna. In this paper, measured data with moving using a channel sounder at 20GHz is analyzed for a low base station antenna installed in an urban street cell environment to clarify the radio wave propagation characteristics., 2020 International Symposium on Antennas and Propagation (ISAP) 25-28 Jan. 2021 Osaka, Japan

As the data capacity of optical access and wireless access continues to increase, optical and wireless convergence systems have become a research hotspot in recent years because of their large capacity and flexibility in optical communications. The terahertz communication system can provide data communication close to the optical fiber communication capacity, and the transmission rate can be hundreds of Gbps to Tbps (Boulogeorgos in IEEE Commun. Mag. 56:144–151, June 2018).

The ultimate goal of communication network development is to achieve real-time, high-speed and reliable information access anytime, anywhere.

The demands of dynamic performance, fast charge, lightweight, compact, energy efficiency for electric vehicles and the application of large capacity and high specific energy batteries make the safety of power batteries receive more attention. The critical identification and diagnosis become the key technology for battery thermal safety control. When exploring analytical methods for overheating diagnostic prediction, the temperature rise and venting events are mainly considered.

Emerging persistent memory (PM, also termed as non-volatile memory) technologies can promise large capacity, non-volatility, byte-addressability and DRAM-comparable access latency. Such amazing features have inspired a host of PM-based storage systems and applications that store and access data directly in PM. Sorting is an important function for many systems, but how to optimize sorting for PM-based systems has not been systematically studied yet. In this paper, we conduct extensive experiments for many existing sorting methods, including both conventional sorting algorithms adapted for PM and recently-proposed PM-friendly sorting techniques, on a real PM platform. The results indicate that these sorting methods all have drawbacks for various workloads. Some of the results are even counterintuitive compared to running on a DRAM-simulated platform in their papers. To the best of our knowledge, we are the first to perform a systematic study on the sorting issue for persistent memory. Based on our study, we propose an adaptive sorting engine, namely SmartSort, to optimize the sorting performance for different conditions. The experimental results demonstrate that SmartSort remarkably outperforms existing sorting methods in a variety of cases.

In the article, the authors consider the role of a multimedia textbook in modern education. The priority national project "Education" is being implemented in Russia - the creation and implementation of modern electronic textbooks is one of the priority concepts in this project. Electronic publications enhance interactive features such as modeling, surveys, discussions, and additional multimedia materials. Advantages of electronic textbooks: mobility, large capacity of information; the ability to constantly update content, without purchasing a new textbook and financial expenses; level of visibility: you can only put text, illustrations, diagrams and graphs in a printed publication, but you can also put animation in an electronic publication, which is convenient for visual display of academic subjects. The electronic textbook provides more opportunities for learning within the existing programs, as well as for the development and optimization of the educational process.

Facing serious environmental and traffic problems, urban rail transit companies, with the features of large capacity and high efficiency, have become an important choice for many large cities that are prioritizing public transportation and encouraging green travel options. As the construction speed of rail transit projects accelerates, the demand for materials and devices required for construction and operation is also increasing for urban rail transit companies. Therefore, the scientific selection of suppliers to meet construction and operation demands has become a problem that must be addressed. This paper presents an intuitionistic fuzzy factorial analysis model in a random environment, where correlative phenomena among each of the indicators and a random decision-making environment are considered. The evaluation indicator system of rail suppliers is established by considering the influencing factors. The extracted common factors indicate the nature of the studied object in a most direct way. The suppliers are evaluated from the perspective of the number of intuitionistic fuzzy factors and are ranked by their scores. Finally, the Tianjin urban rail transit company is used as a case study to illustrate the validity and feasibility of the method. The results can help urban rail transit companies improve their existing supplier selection method.

Subway electric passenger cars have a large capacity, high efficiency, high-frequency door set control switch and other characteristics, so it requires the door safety, reliability, low failure rate. This paper mainly aims at the force analysis calculation and structural optimization of the fault of the screw break of the synchronous rod bracket, so as to avoid the same kind of fracture situation.

the topology structure of large capacity battery energy storage converter is analyzed. The DC/AC bidirectional converter control strategy and the different modes of control are proposed. The simulation model is built. Various control methods such as constant current mode and constant voltage mode are verified. The simulation results verify the effectiveness of the control strategy. The grid-connected and off-grid control of high-capacity battery energy storage system is realized. The test results verify the correctness and feasibility of the control strategy, and the experiment shows that the system can achieve stable grid-connected operation.

Fast Fourier Transform (FFT) is one of the core algorithms in digital signal processing. The traditional FFT processing method can no longer meet the data processing requirements, so the implementation and optimization of the better performance radix-4 FFT algorithm has very important research value. Based on FPGA technology, this paper proposes a design scheme of radix-4 FFT algorithm processing system. By optimizing the butterfly processing unit, the system realizes a high-performance FFT algorithm processing system with characteristics of faster operation speed, higher calculation accuracy, easy hardware implementation and large capacity compared with the traditional FFT processing method. It is well suited for scientific computing, image processing and other fields.

High performance optical waveguide devices are desired for realizing large capacity optical communication system. Automatic optimal design approaches have been intensively studied so far. In order to efficiently design optical waveguide devices, we propose an automatic optimization approach based on Bayesian optimization and beam propagation analysis.

It is undoubtedly necessary to improve the black start ability of power grid after large-scale failure to ensure the safe operation. Based on the analysis of the problems faced by the traditional black start scheme, it is proposed to allocate large-capacity energy storage in gas-fired power plants to assist the black start. Aiming at the black start scheme with energy storage participating in power grid recovery, an integrated energy storage control strategy based on the combination of droop voltage regulation control and V/f control is proposed. Depending on the control of the key links of black start, such as the stable establishment of auxiliary bus voltage, the start-up of large -capacity auxiliary machines and the charging of no-load transformers and transmission lines, a series of problems in the process of traditional black start have been improved and the recovery of power grid after failure has been accelerated. Finally, according to the simulation results, the feasibility and effectiveness of the proposed control strategy are analyzed.

An important problem of network traffic is how to efficiently carry massive amounts of data traffic generated by Peer-to-Peer (P2P) services in high-speed and large-capacity optical access networks. P2P file-sharing traffic is regarded as one of the biggest bandwidth consumption in the world. Internet service providers can reduce the bandwidth burden in the feeder fiber by localizing the network traffic. In this paper, we propose an enhanced redirection strategy based on the optimized MPCP protocol (ERS-MPCP) to redirect the traffic into the access network and reduce the latency. A Markov chain is used for mathematical modeling. In the proposed strategy, we build a simulation platform for network simulation. Simulation results show that our strategy can improve the overall redirection success rate by up to 9%, thereby reducing the data traffic burden on the core network.

This research focuses on the usage and importance of RPA (robotic process automation) to fine-tune tedious work such as filling in forms of education workshops. The research looks at how RPA can be used to prepare learning documents and materials used by large numbers of participants. The study was conducted using an RPA to test cases with repetitive routines. It was proposed that the process of automated work management and AI would result in a more efficient and effective workflow while reducing the error margin. The research will show that RPA can manage a large capacity of documents with very high accuracy, which will be beneficial for educational workshops with many participants requiring a great deal of material preparation and exportation for analysis afterward.

The Field Programmable Gate Array (FPGA) devices are being used more and more, especially in applications that require real-time data processing, for example in communication systems. To meet the memory requirements for FPGA systems, the onboard memory can be used, but it cannot be expanded easily by adding some cards. More useful are Secure Digital (SD) cards that are detachable and can be replaced easily. In this paper, we have designed and implemented a FPGA controller that allows writing and reading SD cards using the SPI protocol. The main objective is to provide a storage solution for FPGAs, to store large files on large capacity, cheap, portable and easy to use storage devices. Using the SPI protocol, the system can access multiple SD cards with a minimum usage of data lines from FPGA. The hardware design and implementation are developed on a Xilinx AC701 platform with Artix-7 FPGA, using VHDL language. The FPGA controller was tested with more SD cards and the results shown that the system can run without errors.

The rectifier transformer is the power transformer of the rectifier equipment. The characteristic of the rectifier device is the AC input, DC output by rectifying the original. Converter transformer and voltage regulation transformer connect through oil and gas casing of Shanxi medium aluminium Huarun Co., Ltd. In order to solve the problems such as high test current caused by 200 kW no-load loss, insufficient capacity of single frequency conversion power supply, complicated field environment, and the great interference, a complete test plan is presented according to the conditions of the field, and the whole process of the successful test is described in detail. The key problems about the selection of test power, the selection of test frequency, and the choice of pressure mode are emphasised. The on-the-spot partial discharge test of the converter transformer has been successfully completed, which provides valuable experience for the test of large capacity transformer in the future.

Tapping secret message information often occurs in communication media. Safeguarding information or data distributed is very important to maintain confidentiality, integrity and authenticity. In steganography, there are several digital media that can be used as covers to hide the existence of a message, such as: Image, Audio, Text, and Video. The cover media research used in digital imagery is the Bit-Plane Complexity Segmentation Method. Bit-plane complexity segmentation (BPCS) is a steganography technique that has a large capacity, because it can hold confidential data with a relatively large capacity when compared to other steganography methods. It is expected that this research can minimize the leakage of important information that is very confidential and detrimental if it is known by others.

DC ice melting is an effective technical method against ice disaster on transmission lines. To satisfy the demand for simultaneous de-icing and reactive power compensation for substations, this paper proposed a large-capacity low-cost DC deicer with reactive power compensation, which is mainly composed of rectifier transformer, Static Var Generator (SVG) and diode rectifier. In the proposed topology, SVG and diode rectifier share the rectifier transformer, but rectifier transformer capacity is not increased compared with a single deicer. This paper firstly presents the proposed topology and analyzes its advantages. Then, the rectifier transformer design is introduced, and the SVG control strategy is presented. Simulation results for the proposed device are presented, and an engineering devices with a capacity of 21.8 MVA developed for the 220 kV Fuchong substation is described. The simulation and application results indicate that the proposed devices work well.

Hybrid storage satisfies the requirements of real-time processing and large capacity put forward by big data. But the widely used big data storage platform HDFS still cannot efficiently utilize emerging devices in hybrid environment. And most of existing hybrid storage researches also fail to consider the asymmetric characteristics among devices and data. This paper proposes a preference model to quantitatively weight the storage performance imbalance when data are distributed on different devices, and then distributes data on storage device whose performance efficiently matches data access characteristics. The implemented Preference-Aware HDFS (PAHDFS) shows high performance, efficiency and scalability in experiments.

Truck-drone hybrid delivery is a hybrid one combining the advantages including large capacity of truck and high travel speed of drone together. Vehicle routing problem with drones (VRP-D) is a common one in the above delivery system. In this paper, VRP-D is addressed and a new dynamical artificial bee colony (DABC) is employed to minimize the overall operational cost. Two bee swarms are produced and an effective evaluation process is used to determine employed bee swarm and onlooker bee swarm dynamically. Variable neighborhood descent is constructed by using 15 neighborhood structures and adopted in employed bee phase and onlooker bee phase in different ways. A number of experiments are conducted on 112 instances and the computational results reveal that DABC provides new best solutions for 37 instances and has promising advantages on VRP-D.

Full power converter wind turbine is the main type of wind power, so the simulation calculation needs to establish accurate model parameters. This paper analyzes the model structure of PSASP program according to its low voltage ride through control and physical characteristics, and puts forward the parameter identification method of LVRT characteristics of full power converter wind turbine, and to use the LVRT data of 5. 5MW unit for parameter identification and simulation verification. This paper proposes that the electromechanical transient simulation can ignore the part of the generator model of the full power converter wind turbine, and simulates the grid side converter with the controlled current source. The main characteristics of LVRT are determined by the control system of the converter. In order to do the parameter identification, it is necessary to calculate and analyze the control characteristics of multiple measured data. First, determine the control mode, then determine the control parameters to complete the parameter identification. In this paper, the modeling conditions and model structure of the full power converter wind turbine are confirmed. The correlation between the parameters during the LVRT fault and the parameters during the LVRT recovery period and the LVRT characteristics is analyzed. In this paper, a parameter identification method is proposed to analyze the active current and reactive current during the LVRT fault, which has strong physical significance and operability. Based on the actual LVRT characteristics of 5. 5MW wind turbine, the parameter identification and simulation are carried out to verify the correctness of the method.

Emerging persistent memory (PM, also termed as non-volatile memory) technologies can promise large capacity, non-volatility, byte-addressability and DRAM-comparable access latency. A host of PM-based storage systems and applications that store and access data directly in PM have been inspired by such amazing features. Sorting is an important function for many systems, but how to optimize sorting for PM-based systems has not been systematically studied. In this paper, we conduct extensive experiments for many existing sorting methods, including both conventional sorting algorithms adapted for PM and recently-proposed PM-friendly sorting techniques, on a DRAM and real PM hybrid platform. The results indicate that these sorting methods all have drawbacks for various workloads. Some of the results are even counterintuitive compared to running on a DRAM-simulated platform in their papers. To the best of our knowledge, we are the first to perform a systematic study on the sorting issue for persistent memory. Based on our study, we summarize principles on selecting the optimal algorithms and propose an adaptive sorting engine called PMSort to perform the selecting operation and reduce failure recovery overhead in PM. We conduct extensive experiments and show that PMSort can select the best sorting algorithm in a variety of cases.

Abstract.This paper aims at the high efficiency of field balancing for turbo-generator with large capacity currently, and introduces the strategies and key techniques of the rotor system balancing with practical cases of power plant in field. The acquisition, analysis and former processing of the original vibration data for balance calculation are included. Furthermore, they involve complete measuring points and conditions, accurate judgment for the types of unbalance exciting force and selection of stable vibration data, all these could reduce the blindness of balancing effectively. The strategies and techniques also contain the determination for axial plane of unbalance by the modal method, then the optimal steps and the plane of adding weight are chosen during the implementation of balancing. Besides, this paper also introduces the analysis and selection of influence coefficients and the phase of trial weight, these can help determine the final correction weight accurately in order to guarantee the balancing process prompt and efficient. Meanwhile, the restriction of practical location for adding weight and construction period of maintenance and production for the units should be considered during the high efficiency balancing in field. These strategies and techniques of high efficiency balancing have practical application value in promoting the technology of field balancing for turbo- generator units with large capacity.

Inland waterway transportation system has the advantages of low investment, large capacity, low cost, and low energy consumption, which is an important part of modern comprehensive transportation s...

The modern market of transport services requires the saturation of the car fleet, a specialized type of construction designed to carry a special kind of cargo, for example, heavy cargo containers, various automotive equipment, etc. It is necessary to increase the speed of movement and safety of the goods carried. A review of the work related to the improvement of the running parts of freight cars showed that over the past 50 years a large number of different types of freight wagon carriages have been developed. At the same time, the main attention was paid to the improvement of individual elements during the creation of bogies, and the problem of the wear of the part of the trolleys was solved while preserving the unchanged ideologues lay in the CRI-Х3 trolley. However, the question of the choice of constructive schemes and rational parameters of the spring suspension of bogies is not completely resolved.

We report on our recent progress in high-speed and large-capacity silicon-photonics-based integrated device technologies targeting large-capacity transmission in both datacom and telecom networks fields. A 70 Gbaud NRZ operation of all-silicon Mach–Zehnder modulator was demonstrated using forward-biased PIN diodes accompanied by passive equalizers. A clear optical eye opening was obtained owing to a broad electro-optic bandwidth of 37 GHz. We also successfully developed co-package-type 16-channels parallel silicon integrated transceivers and demonstrated simultaneous 400 Gbps operation. A novel demultiplexer capable to resolve phase-error-induced impairments is reported. With a simple control algorithm combining the heaters with monitored powers, crosstalks of as low as -58 to -49 dB have been obtained. This technology enabling temperature insensitivity and high yields drastically improves performance and cost of wavelength division multiplexing (WDM) transceivers.

As the dominant information carrier in water, the acoustic wave is widely used for underwater detection, communication and imaging. Even though underwater acoustic communication has been greatly improved in the past decades, it still suffers from slow transmission speeds and low information capacity. The recently developed acoustic orbital angular momentum (OAM) multiplexing communication promises a high efficiency, large capacity and fast transmission speed for acoustic communication. However, the current works on OAM multiplexing communication mainly appear in airborne acoustics. The application of acoustic OAM for underwater communication remains to be further explored and studied. In this paper, an impedance matching pentamode demultiplexing metasurface is designed to realize multiplexing and demultiplexing in underwater acoustic communication. The impedance matching of the metasurface ensures high transmission of the transmitted information. The information encoded into two different OAM beams as two independent channels is numerically demonstrated by realizing real-time picture transfer. The simulation shows the effectiveness of the system for underwater acoustic multiplexing communication. This work paves the way for experimental demonstration and practical application of OAM multiplexing for underwater acoustic communication.