Motivation: The Key to Improve Students’ Outcomes

Most students in Vietnam have been exposed to English since the third grade. However, their outcomes are still limited due to a lack of motivation to study English. This presentation will suggest a number of policies to improve student achievement

On the Interference Alignment Designs for Secure Multiuser MIMO Systems

In this paper, we propose two secure multiuser multiple-input multiple-output transmission approaches based on interference alignment (IA) in the presence of an eavesdropper. To deal with the information leakage to the eavesdropper as well as the interference signals from undesired transmitters (Txs) at desired receivers (Rxs), our approaches aim to design the transmit precoding and receive subspace matrices to minimize both the total inter-main-link interference and the wiretapped signals (WSs). The first proposed IA scheme focuses on aligning the WSs into proper subspaces while the second one imposes a new structure on the precoding matrices to force the WSs to zero. When the channel state information is perfectly known at all Txs, in each proposed IA scheme, the precoding matrices at Txs and the receive subspaces at Rxs or the eavesdropper are alternatively selected to minimize the cost function of an convex optimization problem for every iteration. We provide the feasible conditions and the proofs of convergence for both IA approaches. The simulation results indicate that our two IA approaches outperform the conventional IA algorithm in terms of average secrecy sum rate.Comment: Updated version, updated author list, accepted to be appear in IEICE Transaction

Foreword

This work reports on the performances of ohmic contacts fabricated on highly p-type doped 4H-SiC epitaxial layer selectively grown by vapor-liquid-solid transport. Due to the very high doping level obtained, the contacts have an ohmic behavior even without any annealing process. Upon variation of annealing temperatures, it was shown that both 500 and 800 °C annealing temperature lead to a minimum value of the Specific Contact Resistance (SCR) down to 1.3×10−6 Ω⋅cm2. However, a large variation of the minimum SCR values has been observed (up to 4×10−4 Ω⋅cm2). Possible sources of this fluctuation have been also discussed in this paper

ARSENIC REMOVAL FROM WATER BY CHEMICAL OXIDATION AND ADSORPTION ON IN-SITU FORMED FERRIC HYDROXIDE

Joint Research on Environmental Science and Technology for the Eart

Differences In Hepatitis B Screening And Diagnosis Among Practices Serving Asian And Non-Asian Patients Using Electronic Health Records

Background: Racial disparity in chronic infection with hepatitis B virus is a major public health issue in the United States. Limited data exist on rates of screening and diagnosis collected from providers instead of patient self-reported surveys. Methods: Data were extracted from electronic health records (EHRs) of practices in New York City for 2013. Three measures of hepatitis B (Hep B) screening and diagnosis were collected: 1) lab tests for hepatitis B virus surface antigen (HBsAg); 2) diagnosis via International Classification of Diseases, 9th edition (ICD-9) codes; and 3) of lab tests ordered, positive results. Generalized estimating equation models were used to analyze predictors of Hep B screening and diagnosis across three patient groups: Asians who preferred Chinese, Asians who preferred English, and non-Asian patients. Results: The study population consisted of 377 practices, with an average of 20% (SD = 33%) Asian patients per practice. On average, 5% (SD = 10%), 0.2% (SD = 0.7%), and 1% (SD = 5%) of patients in a practice were screened, diagnosed, and HBsAg positive respectively. Chinese-preferred Asians were significantly more likely to undergo screening compared to English-preferred Asians (beta=0.97, p-value \u3c.01) or non-Asians (beta = 0.89, p-value \u3c.01). They were also more likely to be diagnosed compared to English-preferred Asians (beta = 1.78, p-value \u3c.01) or non-Asians (beta = 2.96, p-value \u3c.01). Discussion: Practices were significantly more likely to screen for and make diagnosis of Hep B among Asian sub-groups, but rates remain low. This indicates a need for educational interventions targeting providers or by integrating Hep B quality metrics in EHRs. This analysis of 2013 data provided a baseline estimate of health care delivery patterns of Hep B of a hard-to-reach and high-risk population prior to screening recommendation changes in 2014

Advanced control structures for induction motors with ideal current loop response using field oriented control

Field oriented control (FOC) is widely used for high performance induction motor (IM) electrical drive systems. Typically, FOC uses linear controls and space vector modulation (SVM) to control the fundamental components of the stator voltages. This work shows that based on a fast and precise inner current loop response one may flexibly employ different advanced control methods, to achieve high performance outer loops (speed and flux control). In this paper, novel approaches based on dead-beat scheme for the current loop combining with exact linearization, backstepping controls, and fatness-based methods for the outer loop are proposed. By comparing with classical PI control, the proposed method shows the outstanding features of system response such as fast, accurate and decoupling properties. The performance evaluation is given by experimental results

Experiment study of an automatic guided vehicle robot

This paper presents the design and control of an autonomous robot-automation guided vehicle (AGV) with a load of 50 kg and a DC motor in theory and experiment. This robot has the function of transporting tools and equipment in the factory. This robot is designed and built control system including hardware and software. In which microcontroller type STM32F407VG is selected to control the primary system. The AGV robot is controlled to move according to the required trajectory. A PID controller controls the DC motor. The AGV robot moves precisely according to the routes set in the factory. At the same time, the AGV has good obstacle avoidance. The results of the proposed solution are proven through simulation and experiment

Design and fabrication of a moving robotic glove system

This paper presents the research, design, and manufacture of a robotic hand to control movement with a glove. The moving glove-controlled robotic hand is based on two main parts: the hand mechanism and the control circuit. The control glove unit includes an Arduino nRF24l01 microcontroller module and five flex sensors for five fingers. These sensors are used to collect data about the curvature of each finger. Then those data will be received by the Arduino microcontroller and sent by the nRF24l01 module. The hand's microcontroller will process that information and control five servo motors so that the five fingers of the robotic hand are moved. The result of this research is to produce a robotic hand that accurately simulates the curvature of a user's finger and mimics the motion of a glove well. Moreover, the robot hand can grip objects of different sizes (from 0.1 to 1 kg) and shapes, from which this robot helps users easily manipulate objects

An implementation of packet-switched communication for pilot protection at Tennessee Valley Authority

The utility network has long relied on Time Division Multiplexing (TDM) such as T1 and Synchronous Optical Network (SONET) as the main channel to transmit and receive data in a communication system. However, TDM technology is aging and its equipment becoming obsolete as vendors transition to Packet-Switched Networks (PSN) to make way for Ethernet-based network communications. Teleprotection is a critical element for a reliable power system as it provides high-speed tripping for faults on the protected line and is applied in various pilot protection schemes. Protection schemes cannot perform at their best without a fast and reliable communication system. The transition from a circuit-switched technology like SONET to a packet-based technology like Multiprotocol Label Switching-Transport Profile (MPLS-TP) has caused reservations for protection engineers as they express their concerns for lacking guaranteed 100% availability and potential latency. This paper will address this issue and the consistent test results at the Tennessee Valley Authority (TVA)\u27s lab have proven to satisfy the communication requirements in a teleprotection system. Teleprotection traffics make to its destination in order in microseconds, the symmetrical delay is less than 1µs, and especially the recovery from a failure occurs under 50ms (3 cycles). The results reassure the protection engineers that the Ethernet migration is necessary yet provides a better performance compared to the legacy system