Miracle-dz/UniFAR-FTUs huggingface dataset:
Research on Adaptive Equalization of Lithium Battery Packs Based on Ant Coloy System

Due to the monomers difference caused during the production process, the inconsistencies of Lithium batteries in remaining capacity can affect the service life of battery packs and cause damage or even explosions. A new mod-ulnar equalization circuit, composed of improved DC-DC converters with the adaptive equalization control strategy based on ant coloy system (ACS), is proposed to enhance the performance of battery packs. The equalization circuit has the advantages of simplicity and easy implementation. It achieved the controllability of bidirectional energy equalization and current size. First, the circuit’s structure and working principle are introduced. According to ACS, the simulation model of this balancing circuit with four batteries in series is built. The simulation results showed that equalization time is shortened by about 60% compared with the traditional control strategy. Then, a small-scale experimental circuit with 8 batteries was built to vertify the simulation results, and the batteries were balanced under charge, idle, and discharge states, respectively. The experiment results verified the correctness and feasibility of the method.
Demonstration of effect of oversampling on jitter removal for Multitaper GFDM system using SDR

Generalized frequency division multiplexing (GFDM) is a flexible block structured multi carrier modulation scheme and is the foremost contender for 5G physical layer. This transmission scheme reduced unwanted out-of-band (OOB) radiations emission at the cost of adding non-orthogonality, which in turn increased the bit error rate (BER). The usage of discrete prolate spheroidal sequences (DPSSs) as prototype filters named as Multitaper GFDM (MGFDM) was found to improve the orthogonality of the system. In this paper, real time transmission of MGFDM is carried out using software defined radio (SDR) by implementing various channel estimation and synchronization algorithms. We employed all the correction algorithms using a windowed preamble to satisfy low OOB requirements. However, the high speed performance of MGFDM system is heavily effected by jitter noise, since it results in improper sampling instances. This article underlines the jitter noise power reduction using oversampling with the supported mathematical expressions and simulations. We observed that the integer oversampling would mitigate the noise power in linear fashion by increasing the sampling rate. The proposed theory is validated using National instruments (NI) universal software radio peripheral (USRP) 2953R hardware interfaced with Labview software.
Graphene-ZnO NWs Film for Large-Area UV Photodetector

This work demonstrates large-area (~ 4cm2) UV photodetector by heterogenous integration of graphene-ZnO nanowires (NWs) using a facile and cost-effective method. Owing to the low and wavelength-independent light absorption, it is difficult to obtain high-performance graphene-based photodetector (PD). The research presented here addresses this challenge by integrating light sensitive material (ZnO) on graphene. The huge sensitivity of ZnO NWs to UV light, combined with the high carrier mobility of graphene, enable the UV PD with a photoresponse up to 2100 A/W, and fast response times down to millisecond.
Identification of Technology Features to Understand and Maintain Software Architectures

For software architects involved in maintaining existing software systems, understanding the architecture is a crucial task. They have to comprehend the evolution of a system and the rationale behind design decisions to avoid architecture erosion. This is challenging due to frequently outdated documentation and incomplete knowledge about the system, which especially applies to long-living systems. Therefore, it is necessary to retrieve the missing information straight from the existing system. Most existing approaches are limited to reconstruct the structure of a software system by preferably analyzing static dependencies between components, without considering their behavior. However, the usage of technologies determines the behavior of a software system. In this paper, we propose an approach to identify technology features in existing systems. Used technology features are fundamental facts which support architects to understand the software architecture and to find alternative technology solutions. We provide tool support and present first results of the identification of technology features in open source systems.
Evaluation of IGFTT Keypoints Detector in Indoor Visual SLAM

Features detectors are key parts of a Visual System of Simultaneous Localization and Mapping (VSLAM). Matching Points of interest (POI) in the image are used by visual odometry to estimate the movement of a robot through camera movement, and to recognize places already visited. It is extremely important to VSLAM the quality evaluation of these detectors, in order to determine the best one to be used in a given context, because the quality of the map generated by the system depends on the POI. Recently introduced feature detector known as Improved Good Features to Track (IGFTT) presents promising results. This work evaluates the IGFTT detector in the scope of a Visual SLAM system in internal environments, comparing it with popular detectors in the academic community, such as SIFT, SURF, FAST, AGAST, GFTT. A public database is used as a benchmark with an open source VSLAM system. The quality of each detector is determined using as metric by the VSLAM pose and trajectory errors, the runtime (detection, description and POI correspondence), the repeatability rate of the detected POI, the probability of their survival in future frames and the number of successive nodes in the scene graph. The tests identify the good qualities and deficiencies of each analyzed detector. In the overall ranking, the SURF comes first, secondly the IGFTT2, a proposed refinement of the IGFTT, and thirdly the original IGFTT.
Integrating TicToc with Parallel Logging

A transactional system consists of a concurrency control system and a recovery system. TicToc is one of the state of the art concurrency control protocols today, but it lacks recovery system. We studied the ways to integrate TicToc and recovery system. For efficiency, we adopted a parallel write ahead logging scheme for the recovery system. There are two methods to optimize the logging. First method is early lock release which executes lock release early on data objects. Second method is group commit which executes batched logs transfer to storage from memory. We integrated a transactional system consisted by TicToc and P-WAL logging system assuming non-volatile memory. We found that the two optimization methods incur performance degradation when storage access latency is equivalent to that of NVRAM.
Audio Noise-free UPS with Zero-Voltage-Switching Back-to-Back Converter

An audio noise-free Uninterruptible Power Supply (UPS) with Zero-Voltage-Switching (ZVS) back-to- back (BTB) converter is proposed. Firstly its ZVS sinusoidal pulse width modulation (SPWM) scheme is introduced. Using the proposed ZVS-SPWM scheme, all the switches in both the rectifier side and inverter side as well as the auxiliary switch can realize ZVS turn-on with only one commonly shared auxiliary circuit. Besides, the auxiliary switch only needs to operate once in each switching period, which can reduce the extra loss caused by the auxiliary circuit. The ZVS conditions with respect to both balanced and unbalanced load situations are given. A resonant parameter design guideline and a low stray inductance bus bar design is introduced. Finally the proposed UPS system with ZVS BTB converter is verified on a 50kVA experimental prototype.
ORB Algorithm Applied to Detection, Location and Grasping Objects

Grasping objects is a highly used activity in the industry but is often done without the aid of vision, limiting the use to few controlled applications. This paper proposes a practical and fast way to grasp objects with a robotic arm. Using a RGB-D visual sensor, the Kinect, it is proposed to use its point cloud to locate an object pose. To find the object, we propose a feature based method, being the feature extractor the ORB algorithm. Together with RANSAC, it is going to find the object position in the RGB image, and find the pixels coordinates in the point cloud. After the object detection, we propose a way to grasp based on the estimated position by the point cloud and the robotic arm position. To develop the system, ROS and OpenCV are used. We demonstrate, through experiments, the efficiency of the proposed system in a real world application.
Interleaved Flyback Converter with GaN Power Devices

In this thesis, a high output current DC-DC converter with wide input voltage range based on GaN device is implemented. Generally, the volume of converter can be reduced and power density can be improved with higher switching frequency. However, the switching losses will be increased at the higher switching frequency conditions. Therefore, the characteristic of the wide band-gap device with fast switching is applied to reduce switching losses. The topology of an interleaved flyback converter with leakage inductance energy recycled is selected in this thesis. Two series capacitors are connected with input side and the voltage of each capacitor is half of input voltage. Besides, the energy stored in leakage inductance can be recycled to these two capacitors through the clamp diodes. Moreover, the system efficiency can be improved with the interleaved control method and the synchronous rectification technique. Finally, an interleaved flyback with leakage inductance energy recycled based on GaN device is implemented. The specifications of the input voltage range and output are 18VDC to 60 VDC and 5 V/30 A, respectively. The highest efficiency is 94.2% at the light load condition.
Multilayer MoS2 Coated Etched Fiber Bragg Grating Based Hydrophone

This paper demonstrates multilayer Molybdenum disulfide (MoS2) coated etched Fiber Bragg Grating (eFBG) as highly sensitive hydrophone. Multilayer coating of MoS2on eFBG is achieved using sputtering of Molybdenum (Mo) followed by sulfurization at 450°C in an inert gas atmosphere. MoS2coated eFBG subjected to underwater acoustic pressure showed an increase in pressure sensitivity of nearly 20 times at 231Hz in comparison with bare FBG sensors.
A Metamodel to Guide a Requirements Elicitation Process for Embedded Systems

[Context] In the embedded systems (ES) area, more than 50% of problems occur at system delivery and are related to misconceptions in capturing requirements. Therefore, it is necessary to address what should be considered by requirements engineers in the elicitation and specification phases of embedded systems. However, understanding embedded systems and their environment is a strenuous activity. Hence, requirements engineers need to know the core concepts related to ES and also a systematic guide to consider these concepts in the development process. [Goal] This paper presents a metamodel based on a systematic literature review (SLR) that can support the elicitation of ES concepts. Additionally, we used the metamodel as a guide to the development of a requirements elicitation process. [Method] We used the studies of an SLR as a basis for the metamodel development and their concepts as input for an investigation of actions that are suitable to be used in our elicitation process. The proposed metamodel concepts were evaluated by a domain expert, and we applied the actions of the process to elicit requirements of an infusion pump system. [Results] The metamodel has 118 entities that represent the RE concepts for ES, and the elicitation process has 49 actions to guide requirements identification and definition. [Conclusion] The metamodel can be used by practitioners to check if they are eliciting the appropriate information for the development of embedded systems. Moreover, it can assist future research. Besides, the process can help organizations in improving their requirements practices to support completeness and correctness of ES elicitation.
Educational Robotics Insertion in High Schools to Promote Environmental Awareness about E-Waste

The inadequate disposal of obsolete electronic materials over the years has brought negative consequences to the environment. The EDUCABOT3D project seeks, in this sense, to disseminate the necessary knowledge about environmental awareness, through actions of reuse of electronic waste components, and the proper disposal of non-reusable items. By means of a booklet, called the Correct Disposal Booklet for e-waste, the risks brought to nature are exposed when e-waste is incorrectly disposed, as well as exposing ways to reuse e-waste, where to discard non-reusable items, among other relevant information. A mobile robot chassis has been modeled for 3D printing, using two ways of control between sensors and actuators, one with a rapid prototyping board and another assembled with reused components in a printed circuit board. The reuse of e-waste, applied to robotics, is a matter of great community interest, as it may encourage young people to reuse their obsolete devices and deliver them to appropriate places for recycling. As result, the concepts of computing and environmental education are disseminated by means of presentations, teaching classes and booklet distribution in high schools.
Modular Knee-Rehabilitation Device: Configuration and Workspace of assisted physical therapy routines

Knee injuries are common in people of all ages, due to physical activity and other reasons. In all cases, physical therapy is prescribed but it will depend on the type of injury suffered. Latest research in robotics has developed assistive devices to contribute to improving the patient’s quality of life. In this paper, we propose a five-bars-linkage knee rehabilitation device, which is reconfigurable according to the patient’s height. We present the kinematic modeling of the device to show that it can reproduce certain exercises or routines prescribed at physiotherapy during the knee rehabilitation according to a processor developed. For this, we show the corresponding workspace and the required mechanical configuration of the five-bars-linkage system. To validate the functionality of the processor and of the mechanism, we implement a real case routine performed by a healthy subject. We use the hip and knee angular positions to process them and show the feasibility of the system, obtaining and comparing the corresponding workspaces.
Performance Evaluation of 802.11ah Physical Layer Phase Encryption for IoT Applications

In the Internet of things (IoT) applications where things are connected and exchanged data wirelessly, security places an important role. In addition, IoT sensors have limitation on the power source and computing ability. Therefore, developing a wireless communication transceiver which is high-security, low power consumption, and low complexity for IoT sensors is significant. With the advantages such as long range, low power, and low-cost, IEEE 802.11ah is a promising candidate for developing IoT sensor’s wireless transceiver. However, the current version of 802.11ah standard does not focus on enhancing the system security. In this research, we solve that problem by proposing a low complexity and high-security encryption method at the physical (PHY) layer of 802.11ah. Because the encryption is processing at the PHY layer, we built the simulation to evaluate the effect of the encryption method to bit error rate (BER) and packet error rate (PER) performance of the system. Our research shows that the implementation of our encryption does not affect to the BER and PER performance of the system while some conventional methods do. In addition, the simulation also shows that unexpected users are entirely unable to obtain the transmitted information without the correct key.
Visual-Inertial Fusion for Indoor Autonomous Navigation of a Quadrotor Using ORB-SLAM

This brief addresses the accuracy of the pose estimation of a Low-Cost Quadrotor using visual SLAM and sensor data fusion for making an autonomous indoor navigation in a known GPS-denied environment. To perform this approach, two kinds of modules are employed. For the former, a Simultaneous Localization and Mapping (SLAM) system is used. This SLAM system uses Oriented Fast and rotated BRIEF (ORB) features, also known as ORB_SLAM. The second module is Extended Kalman Filter (EKF) that is applied for combining the obtained pose from ORB_SLAM and Inertial Measurement Unit (IMU). Since in this paper the SLAM process is performed by the frontal monocular camera of Quadrotor, so developing scale factor estimation in order to calculate the scale of the map with minimum error is necessary. In addition, a Proportional Integral Derivative (PID) is utilized to conduct the maneuver of the robot. All of these processes are done by sending data via Wi-Fi to a ground station in order to perform the data processing. To show the performance of the proposed algorithm, two experiments are carried out on an AR-Drone 2.0 quadrotor. The first one is position holding that shows the robustness of the estimated position of the system in hovering situation after take-off. The second one is an indoor trajectory tracking that illustrates the difference between the downward camera output position and the estimated position.
Linking Census Data based on Similarity Threshold Method

Historical censuses consist of individual facts about a community. It provides knowledge concerned with the nation’s population. These data apply the reconstruction features of a specific period to trace their ancestors and families changes over time. Linking census data is a difficult task as common names, data quality and household changes over time. During the decades, a household may split multiple households due to marriage or move to another household. This paper proposes an approach for data cleaning, standardization and census data linking across time. This computes similarity of selected attributes with approximate string similarity matching methods such as Q-gram, String extract match, Longest common subsequences and Gaussian probability. Then, the matches and un-matches records are determined by similarity threshold method. The results of the experiment show which optimal threshold value is effective for household linkage.
Three-Level ZCS Converter Suitable for Medium Voltage DC Distribution Network

A novel three-level zero-current-switching (ZCS) converter, operating in discontinuous current mode, is proposed for the application of distributed photovoltaic power accessing the medium voltage dc distribution network. The proposed converter is composed of a traditional neutral point clamped (NPC) three-level (TL) circuit and an auxiliary circuit, owning 6 switches and 2 transformers. By controlling the auxiliary circuit with Pulse width modulation (PWM), ZCS can be reached for the basic TL circuit, which delivers most of the power, with the switching loss of the converter remarkably reduced. The influence of turn’s ratio the auxiliary transformer on the switch current is discussed in detail, and the parameters design principles are put forward, which is verified with PLECS simulation results. Finally, a prototype of 300 V-1500 V/1500W is built to verify the performance of the proposed converter.
Live Demonstration: An IoT Platform for Environmental Monitoring Using Self-Powered Sensors

Monitoring of environmental conditions has become increasingly crucial because poor environments can lead to severe health issues [1]. A wireless sensor network (WSN) is a promising solution to collect useful environmental information such as temperature, humidity, etc. In this live demonstration, we demonstrate a self-powered and low-power wireless sensor network system for environmental monitoring dedicated to Internet of Things (IoT) applications.
A Novel Control Method for Eliminating DC Bias in Dual-Active-Bridge DC-DC Converters

This paper proposes a novel transient current control method for dual-active-bridge (DAB) dc-dc converters. When sudden load transients or reference change, the dc bias of inductor current will occur under the traditional control method, which may cause induce magnetic-flux saturation and excessive current spike in the loop. However, a new control method brings the benefit of dynamic performance when disturbance occurs. It can fast achieve new steady state and remove dc offset in dynamic state effectively within half of cycle for inductor current hence preventing magnetic-flux saturation. In this paper, the static and dynamic characteristics of the phase-shift DAB are first analyzed, then the causes of dc bias under the traditional control method are analyzed in detail. On the basis of analysis results, a novel transient control approach is presented to limit the current transient interval in half of switching period. Finally, the experimental model is established and the theoretical analysis is verified by experimental results.
Game Analysis on Sales Return Involving B2C E-Commerce Seller, Buyer and Platform

B2C E-commerce sellers, buyers and platforms have been concerned about the return problem involved in online shopping. Investigation into sales return through B2C platforms with an aim to figure out the reasons behind it comes to a conclusion that the excludability of benefit of buyer and seller, the influence of Matthew Effect, the information asymmetry between buyer and seller, and the phenomenon of sellers sticking to low-price strategy while the buyers dependent on sales return are four reasons for keeping high return rate. Game analysis on B2C e-commerce platform, seller and buyer shall get underway. First, an income matrix covering the combination of the principle of liability without fault and the doctrine of presumption followed by contracting parties will come into being based on the game analysis is on sellers and buyers to reach the Nash equilibrium under rational state of both parties. Secondly, a conclusion that "the buyer's return action is a rational conduct" will arrive based on the game analysis on sellers and platforms. Lastly, the research finds that the return problem can be alleviated through three stages of strategy, including the rational guidance of customers before consumption, the adjustment of customer expectation in consumption and the promotion of product service after consumption.
De-re-coupling Modulation Method of Double-rising-edge Phase-shifted SPWM for Current-Source Matrix Rectifier

In view of the existence of the safe commutation problem in the matrix rectifier, in order to eliminate the voltage spike at both ends of switching tube caused by leakage inductance current of transformer during mode switching, on the basis of the topology of single-phase current-source high-frequency link matrix rectifier, a de-re-coupling modulation method for SPWM with double-rising-edge phase-shifted is proposed. The natural commutation is realized and its decoupling principle is described. The modulation and principle of SPWM de-re-coupling with double-rising-edge phase-shifted are described, and the control logic of the modulation method is designed. The working modes of the circuit topology in a high frequency period are analyzed. Finally, simulation and experimental results verify the feasibility and effectiveness of the proposed modulation method.