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Introduction: The COVID-19 pandemic has spread around the world that severely affects people's life and the health system of countries. Enhancing the population’s awareness and prevention behaviors are crucial. This study aims to assess the knowledge, attitudes, and behaviors regarding COVID-19 prevention of outpatients and visitors at the University Medical Center in Ho Chi Minh City (UMC). Methods: A cross-sectional study was conducted on 765 participants who were conveniently selected when they arrived at UMC between March 2021 and April 2021. A questionnaire was developed based on guidelines of Viet Nam Ministry of Health (Viet Nam MOH), World Health Organization (WHO), and other prior studies to evaluate the general knowledge regarding COVID-19 disease, disease prevention, attitude, and behaviors on prevention methods. Results: The results showed low proportions of participants who had good knowledge of COVID-19 disease (29.15%) and prevention measures (38.17%) that were in contrast with a high percentage of positive attitudes (89.08%). There were 22.09% of participants were identified as good preventive behaviors based on seven surveyed measures. An association between prevention knowledge and prevention behaviors was observed when participants with good knowledge showed 2.15 times-higher odds of good behaviors (95%CI: 1.52, 3.04, p-value

Ban Khoang is a mountainous commune in Sa Pa district located in the central part of Lao Cai province, Vietnam. Landslides occur frequently in this area and seriously affect the local living conditions. To help the local authority in developing a landslide disaster action plan, the statistical index method for landslide susceptibility mapping is applied. As the result, the landslide susceptibility zonation (LSZ) map was created. The LSZ map indicates that areas of low, moderate, high and very high landslide susceptibility zones are, respectively, 20.3 km2, 12.4 km2, 15.4 km2, and 5.2 km2; most of the observed landslide areas that are well predicted belong to high or very high landslide susceptibility classes. In detail, 80% observed landslide areas and 78.57% number of observed landslides were well predicted, and the area (AUC) under the receiver operating characteristic (ROC) curve obtained 80.3%. Hence, the high and very high landslide susceptibility classes in the LSZ map can be considered highly believable, and the LSZ map will be reliable to use in the practice.

Online estimation of rotor and stator resistance is essential for indirect vector controlled speed sensorless induction motor drive in the low-speed region. In this paper, a novel modified neural algorithm has been proposed for online estimation of the rotor and stator resistance. The rotor resistance is estimated by a two-layered feed-forward neural network. The stator resistance is estimated using a two-layered recurrent neural network. The learning rates of the neural networks for rotor and stator resistance estimation are modified by a mamdani fuzzy model. Accurate estimation of rotor and stator resistance improved the quality of the indirect vector controlled speed sensorless induction motor drive. The simulation results showed that the rotor and stator resistance estimated with small error compared to the real rotor and stator resistance, improving the quality of the indirect vector controlled speed sensorless induction motor drive.

A cross sectional study was conducted to assess the current status of food raw materialsat cafeteria kitchens of foreign invested enterprises in Hung Yen Province, 2018. The results showed that the rates of leaf vegetables, root vegetables, fruits, and seafood purchased from approvedsuppliers with certificates of food safety eligibility were of 2.3%, 2.9%, 2.4%, and 3.6%, respectively. There were 11.1% of vegetable and fruit supplier shaving certificates of satisfaction of food safety conditions or other equivalent certificates. Only one seafood supplier has been granted a certificate of food safety eligibility. Most of the remaining seafood was purchased from small farms that have not been approved. It is necessary to develop the models of producing, preliminary processing, processing, and trading of food and food materials in the province in a safe direction such as Vietnamese Good Agricultural Practices (VietGAP) in order to satisfy the local food demand.

Introduction Patients with Peutz-Jeghers syndrome (PJS) have high risk of malignancies, including gynecological cancers. Gastric type mucinous cervical adenocarcinoma might be presented in about 11–17% of PJS patients but the literature about this is limited. Case presentation We presented a rare case of a 39-year-old Vietnamese woman with Peutz-Jeghers syndrome who has gastric type adenocarcinoma (GAS) of the cervix. She underwent radical hysterectomy, and the diagnosis was confirmed on final pathology. Conclusions Oncologists and pathologists should recognize this rare clinical scenario for early diagnosis and treatment. This subtype also has an aggressive nature and poor prognosis., Highlights • Gastric type adenocarcinoma of the uterine cervix (GAS) is a rare variant of endocervical adenocarcinoma. • An association exists between GAS and Peutz-Jeghers syndrome. • Careful evaluation by gynecological oncologists is needed for early detection and treatment of this condition.

Itemset hiding is a technique that modifies data in order to remove sensitive itemsets from a database. The traditional frequent itemset hiding algorithms cannot be applied directly into high utility itemset hiding problem. In order to solve this problem, Tseng et al. [8] proposed HHUIF and MSICF algorithms. The important target of high utility itemset hiding process is to minimize the side effects caused by data distortion, including missing itemsets, ghost itemsets, remaining sensitive itemsets, and database accuracy. In this paper, we propose an algorithm, named HHUSI, for hiding high utility sensitive itemsets. The method consists of two steps: (1) identify victim transaction and victim item and (2) modify internal utility of the victim item in the victim transaction. Experiment shows that the performance of this method is better than HHUIF and MSICF.

In this paper we present an analytical method in pricing European contingent assets, whose state variables follow a multi-dimensional L evy process. We give an explicit formula for the hypothetical European \two-price" call option price by means of the conditional characteristic transform. The work not only unies and extends the option pricing literature, which focuses on the use of the characteristic function, but also provides the way to formalize and unify the valuation of the option price, the valuation of the discount bond price, the valuation of the scaled-forward price, and the valuation of the pricing measure in incomplete markets.

This paper proposes a new idea for grading multiple-choice test which is based on a camera with reliability and efficiency. The bounds of the answer sheet image captured by the camera is first allocated using Hough transform and then skew-corrected into the proper orientation, followed by the normalization to a given size. Next, the tick mark corresponding to the answer for each question can be recognized by allocation of the mask which wraps the answer area. The experimental results showed that the proposed system has achieved significant improvement in performance in terms of accuracy, reliability, and elapsed time compared with those of the conventional optical mark recognition (OMR) systems. The proposed system also demonstrated that it can also achieve high accuracy of 99.7% while using non-transoptic answer sheet paper with lower cost.

We analyze a problem of maximization of expected terminal wealth and consumption in markets with some ``imperfection'', such as constraints on the permitted portfolios, labor income, or/and nonlinearity of portfolio dynamics. By using general optional decomposition under constraints in multiplicative form, we develop a dual formulation. Then, under some conditions imposed on the model setting and the utility functions, we are able to prove an existence and uniqueness of an optimal solution to primal and to the corresponding dual problem by convex duality.

We analyze a problem of maximization of expected terminal wealth and consumption under constraints in a general framework including financial models with constrained portfolios, labor income and large investor models. By using general optional decomposition under constraints in a multiplicative form, we first develop a dual formulation under minimal assumption modeled as in Pham and Mnif (2002). We then are able to prove an existence and uniqueness of an optimal solution to primal and to the corresponding dual problem. An optimal investment and consumption plan to the original problem then can be found by convex duality, similarly to the case considered by Kramkov and Schachermayer (1999).

1. Motivation To study experimentally the interactions of the Radio Duty Cycling (RDC), MAC and Routing over Low power and Lossy Networks (RPL) protocols for wireless sensor and actuator networks (WSAN) a test facility is being built in the garden of a countryside house because observations will be easier to interpret far from potentially disturbing radio transmitters and from reflecting structures causing multi-path interferences. The facility consists in a WSAN, with a dozen static motes, positioned all over a 1000 m2 lawn, one mobile mote, affixed on a robotic lawn mower, and one gateway mote, located near a veranda, where computers and test equipment are housed. The position and the transmission power of the static motes should force the RPL routing algorithm to select as many as possible multi-hop routes. As a survey of the relevant literature [1,2,3,4,5,6] did not provide sufficient practical data to implement this last requirement, we undertook themselves a practical study of radio links , inspiredby the experimental work reported in [5] and [6], but using modern motes available on today's market. We believe some of our observations can be useful for anybody designing a WSAN. 2. Experimental set-up Most of the experiments with WSANs in our environment are done with Zolertia Z1 motes [8] running Contiki [9]. As there was no good reason to change this habit, we decided to use the same motes for this project. The Z1 exists in several versions: the simplest one has a built-in antenna, while another has an external antenna. Both were investigated. The quality of a radio link can be characterized by three indicators. Two of them are evaluated by the radio receiver itself: the analog Radio Signal Strength Indicator (RSSI) and the digital Link Quality Indicator (LQI) [7] estimated by the demodulator. The third is directly relevant to the applications: the Ratio of Packets correctly Delivered (PDR). Studies showing that these three indicators do not correlate very well can be found in [8] and [9]. Therefore, whenever relevant, the values of the three will be given. To evaluate these indicators, a point to point unicast link was set up, using the communication functions provided by Contiki rime. The motes were mounted on 1m wooden poles by means of nylon straps. The battery powered transmitter could freely be positioned anywhere in the garden and given any orientation. The receiver was permanently positioned at approximately 1m from the veranda and was connected by a USB cable to a PC recording the received messages. All range measurements were done along one straight line, with no obstacles between sender and receiver, but some additional measurements were done along two other lines for checking influences of unsuspected causes. For avoiding interference with possible WiFi networks all tests were performed in channel 26, the channel which is least susceptible to WiFi interference. The absence of interfering radio fields was monitored during the experiments by means of a SPECTRAN HF-4060 portable spectrumanalyzer from Aaronia. Radio traffic was monitored by a Texas Instruments packet Sniffer with a CC2531DK dongle. 3. The measurements To test a link, the sender transmitted every second a 45 bytes packet. For 50 consecutively received packets the values of RSSI, LQI and the sequence number of the packet were recorded by the PC connected to the receiver. The global values of RSSI and LQI were obtained by averaging the recorded values, while the PDR value was computed by dividing the number of received packets by the number of sent packets. The latter was obtained from the sequence number included by the sender in each packet. For these tests, the radio was continuously left on. 3.1. Directivity measurements The first test aimed at comparing the motes with built-in antenna and those with an external vertical ?/4 whip antenna. Preliminary tests showed that for links exceeding 1m, the motes with built-in antenna needed to be held vertically. For evaluating the horizontal directivity, the properties of the radio link were measured with 8 different orientations of the sender with respect to the receiver. This clearly showed that the internal antenna of the Z1 motes is far from omnidirectional (20 dB difference between the best and worst direction) and that transmission in front of the mote is especially poor. It was suspected that the presence of batteries in front of the internal antenna was the cause of this poor performance, but removing the batteries proved this hypothesis wrong. As the internal antenna would be a source of unwanted and hard to explain artifacts, it was decided to use exclusively motes with an external vertical antenna. As these antennas appeared to be horizontally omnidirectional and to have a main vertical radiation pattern covering approximately 20 degrees, they seemed to be the best choice for a versatile test facility. 3.2. RSSI calibration The next test consisted in verifying the accuracy of the RSSI indications by the receivers. One by one, all motes, under identical conditions, received 50 packets from a single sender. The average values of RSSI for each mote were compared. They all were within a 2 dB margin, except for one mote that gave a 20 dB lower value. The 2 dB margin complies with the CC2420 specifications [7] but the 20 dB were considered an indication of malfunctioning. The antenna or its cable was suspected but substitution proved the problem was elsewhere. 3.3. Range measurements First, the maximal range was evaluated at 0 dBm in an open field. It was found to be 160 m. Thereafter the quality of radio links was measured several times in three different directions, over distances ranging between 3 and 21m with steps of 3 m and with four different levels for the transmitted power (0 dBm, -10 dBm, -15 dBm and -23 dBm). An almost monotonous, but far from predictable, decrease of the RSSI values in function of the distance could be observed, but large differences between measurements done in different directions and/or weather conditions confirmed the affirmation that RSSI values cannot be used to estimate distances [10]. The LQI values did not show a similar pattern: often they were better at medium distances (12m) than nearby (3m). However, most observed values were above 90 which corresponds to a good digital link. The quality of the digital link was confirmed by the PDR values, which were 100% for all links, except for one 21 m link with -23 dB sending power were RSSI (-93 dBm), LQI (60) and PDR (