Road Traffic Control Gesture Recognition using Depth Images

Le, Quoc Khanh,Pham, Chinh Huu,Le, Thanh Ha The Institute of Electronics and Information Engin 2012 IEIE Transactions on Smart Processing & Computing Vol.1 No.1

This paper presents a system used to automatically recognize the road traffic control gestures of police officers. In this approach,the control gestures of traffic police officers are captured in the form of depth images.A human skeleton is then constructed using a kinematic model. The feature vector describing a traffic control gesture is built from the relative angles found amongst the joints of the constructed human skeleton. We utilize Support Vector Machines (SVMs) to perform the gesture recognition. Experiments show that our proposed method is robust and efficient and is suitable for real-time application. We also present a testbed system based on the SVMs trained data for real-time traffic gesture recognition.

Principal Component Analysis for Heart Rate Measurement using UWB Radar

Le Dang Khanh,Pham Xuan Duong 한국지능시스템학회 2020 INTERNATIONAL JOURNAL of FUZZY LOGIC and INTELLIGE Vol.20 No.3

This paper proposes a signal processing approach based on principal component analysis (PCA) for monitoring heart rate using an ultra-wideband impulse (UWB) radar. Vital signals including respiration and heart rate is measured by a UWB radar, and then compressed and projected on the main principal component. This projection helps to significantly improve the signal-to-noise ratio in comparison to other conventional methods such as direct fast Fourier transform and complex signal decomposition. Thus, an accurate measurement of heart rate can be obtained. The proposed approach can help improve about 10 dB of heartbeat signal.

Factors that Affect Customers Satisfaction: An Empirical Study of Export-Import Service Consultant Companies in Vietnam

LE, Thai Thanh Dat,HO, Thi Thanh Ngan,LE, Nguyen Truc Quyen,HUYNH, Thi Khanh Tuyen,NGUYEN, Minh Tri,LUU, Thi Mai Anh,HOANG, Thi Phuong Thao,NGUYEN, Trong Luan Korea Distribution Science Association 2022 The Journal of Asian Finance, Economics and Busine Vol.9 No.6

The purpose of the study is to analyze the significant impacts of expectations, performance, complaints, and fairness that affect consumer satisfaction. The methodology involves reviewing and referencing relevant literature carefully, then proposing a model for customer satisfaction. This study is empirically based on a survey with 50 respondents who work in the field of import and export in the region stretching from the north to the south of Vietnam. The sampling method used in this study is the in-depth interview method. The results show that: (1) expectation has a specific impact on customer satisfaction, (2) performance has a positive impact on customer satisfaction, and (3) complaint which is an intermediary factor between expectation, performance, and fairness has an impact on satisfaction, (4) fairness has a positive effect on satisfaction, in addition, fairness is an extremely important feature when customers choose an import-export service. Research implies that increasing expectations, performance, and fairness results in an improved customer experience and satisfaction when they use the service. It is suggested that the complaint factor continue to be studied and looked into because it still has some effect on satisfaction and is an intermediate variable that changes how the other factors relate to each other.

Violation of Bans on Tobacco Advertising and Promotion at Points of Sale in Viet Nam: Trend from 2009 - 2015

Le, Thi Thanh Huong,Tran, Khanh Long,Phung, Xuan Son,Do, Phuc Huyen,Phan, Thuy Linh,Nguyen, Ngoc Bich,Nguyen, Xuan Lam,Le, Vu Anh,Tran, Thi Tuyet-Hanh Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.no.sup1

Comprehensive bans on tobacco advertising and promotion were introduced through tobacco control legislation in Viet Nam, but it has been established that violations of the bans are very common. This study was conducted to explore the trend in violations of bans on tobacco advertising and promotion at points of sale in Viet Nam in the past six years and to explore any differences in the violation situations before and after the Law on Tobacco Control came into effect on 1st May 2013. Quantitative data were collected through observation of violations of the bans on tobacco advertising and promotion at points of sale in 10 provinces throughout Viet Nam in four survey rounds (2009, 2010, 2011, and 2015). Variation in violation prevalence over time was examined by chi-square test using a Bonferini method. Binary logistic regression was employed to identify the factors that may have influences on different types of violation. A level of significance of p<0.05 was used for all tests in this article. The most common form of violation was the display of more than one pack/one carton of a cigarette brand. Violation of bans on tobacco advertising increased while violations on promotion ban and on displaying tobacco decreased through time. Some factors associated with the tobacco advertising and promotion bans included surveyed years, types of points of sale, regions and areas where the points of sale were located. The enforcement of the bans did not improve even after the issuance and the enactment of the Law on Tobacco Control. This suggests that the monitoring and enforcement of bans on tobacco advertising and promotion at points of sale should be strengthened. Penalties should be strictly applied for violators as indicated in the current tobacco control legislation.

A study on the modeling of a hexacopter

Le, Dang-Khanh,Nam, Taek-Kun The Korean Society of Marine Engineering 2015 한국마린엔지니어링학회지 Vol.39 No.10

The purpose of this paper is to present the basic mathematical modeling of a hexacopter, which could be used to develop proper methods for stabilization and trajectory control. A hexacopter consists of six rotors with three pairs of counter-rotating fixed-pitch blades. This mechanism is an under-actuated, dynamically unstable, six-degrees-of-freedom system. The whole motion of this object consists of translational and rotational motion in three dimensions, where the translational motion is created by changing the direction and magnitude of the upward propeller thrust. The hexacopter is controlled by adjusting the angular velocities of the rotors, which are spun by electric motors. It is assumed to be a rigid body; thus, the differential equation of the hexacopter dynamics can be derived from the Newton-Euler equation. The Euler-angle parametrization of the three-dimensional rotations contains singular points in the coordinate space that can cause failure of both the dynamical model and control. In order to avoid singularities, the rotations of the hexacopter are parametrized in terms of quaternions. This choice has been made considering the linearity of the quaternion formulation and their stability and efficiency. Further, control simulation of a hexacopter applying cascaded-PID control is also presented in this paper.

Effects of Busy Mindset and Self-Worth on Impulsive Buying: In the Category of Hedonic Products

Le Thu Khanh LINH,이형재 한국유통과학회 2020 유통과학연구 Vol.18 No.9

Purpose: The research aims to examine whether perception about busyness can affect the way people view themselves and then make an impact on purchase decision-making. Based on a proposed theoretical framework, the current research examines whether or not perception about busyness affects perceived self-worth and has an impact on impulsive buying. Research design, data, and methodology: The paper conducted a survey in which two scenarios are used for manipulating degree of busy mindset. For analyzing data, analysis of variance and regression analysis are applied, in conjunction with analysis of moderating effects. Results: Busy mindset has a positive effect on perceived self-worth. The effect of busy mindset on perceived self-worth is greater in the group of high perceived social mobility. In the category of hedonic products, perceived self-worth has a positive effect on impulsive buying intention. Conclusions: These results imply that a sense of self-worth can affect impulsive buying behavior on the basis that people sometimes buy things on impulse as a way of self-indulgence or self-reward for their efforts. Managerial implications of the results suggest a busy appeal to consumers would be more effective for hedonic products.

α-Glucosidase Inhibitory Activity of Phenolic Compounds Isolated from the Stems of Caesalpinia decapetala var. japonica

Le, Thi Thanh,Ha, Manh Tuan,Hoang, Le Minh,Vu, Ngoc Khanh,Kim, Jeong Ah,Min, Byung Sun The Korean Society of Pharmacognosy 2022 Natural Product Sciences Vol.28 No.3

In our study, sixteen known phenolic compounds, including quercetin (1), methyl gallate (2), caesalpiniaphenol C (3), 8S,8'S,7'R-(-)-lyoniresinol (4), 7,3',5'-trihydroxyflavanone (5), sappanchalcone (6), sappanone A (7), taxifolin (8), fisetin (9), fustin (10), (+)-catechin (11), brazilin (12), 3,4,5-trimethoxyphenyl β-ᴅ-glucopyranoside (13), 1-(2-methylbutyryl)phloroglucinol-glucopyranoside (14), (+)-epi-catechin (15), and astragalin (16) and one mixture of two conformers of protosappanin B (17/18) were isolated from the stems of Caesalpinia decapetala var. japonica. Their structures were elucidated based on a comparison of their physicochemical and spectral data with those of literature. To the best of our knowledge, this represents the first isolation of compounds 3, 4, 8, 9, and 10 from C. decapetala and compounds 13 and 14 from the Caesalpinia genus. All the isolated compounds were evaluated for their inhibitory effect against the α-glucosidase enzyme. Among them, two flavonols (1 and 9), one chalcone (6), and one homoisoflavanone (7) exhibited an inhibitory effect on α-glucosidase action with an IC₅₀ range value of 5.08-15.01 μM, stronger than that of the positive control (acarbose, IC₅₀ = 152.22 μM). Kinetic analysis revealed that compounds 1 and 9 showed non-competitive α-glucosidase inhibition, while the inhibition type was mixed for compounds 6 and 7.

Researching Arsenic Absorbability of Magnetic Nanoparticles Fe₃O₄ Coated with Oleic and Alginic Coatings

Le Khanh Vinh,Tran Hoang Hai,Le Hong Phuc,Doan Thi Kim Dung,Bui Duc Long,Ly Thi My Huong 한국자기학회 2008 한국자기학회 학술연구발표회 논문개요집 Vol.- No.-

Burned Area Detection After Wildfire Using Landsat 7 ETM+ SLC-off Images

Quoc, Khanh Le,Sy, Tan Nguyen,Nhat, Thanh Nguyen Thi,Thanh, Ha Le The Institute of Electronics and Information Engin 2013 IEIE Transactions on Smart Processing & Computing Vol.2 No.3

The increasing demand for monitoring wildfires and their impact on the land surface have prompted studies of burned area extraction and analysis. To differentiate burned and unburned area, the earlier method of the Moderate Resolution Imaging Spectro-radiometer (MODIS) Burned Area Detection Algorithm was proposed to estimate the change in land surface based on the reflectance energy. The energy, whose wavelengths are sensitive to burning, was selected to calculate the change parameter $Z_{score}$. This method was applied using the MODIS images to produce a MODIS Burned Area product. The approach was to simplify this algorithm to make it compatible with the Landsat 7 ETM+ SLC-off images. To extract the refined version of burned regions, post-processing was carried out by applying a median filter, dilation morphology algorithm, and finally a gap filling method. The experimental results showed that the detailed burned areas extracted from the proposed method exhibited more spatial details than those of the MODIS Burned products in the large U.S areas. The results also revealed the discontinuous distribution of burned regions in Vietnam forests.

Baseline susceptibility of Asian corn borer (Ostrinia furnacalis (Guenée)) populations in Vietnam to Cry1Ab insecticidal protein

Duc Khanh Le,Quang Khai Le,Thi Thuy Hang Tran,Duc Viet Nguyen,Thi Hang Dao,Thi Thuy Nguyen,Xuan Lam Truong,Quang Cuong Nguyen,Huy Phong Pham,Thi Thu Thuy Phan,Gajendra Babu Baktavachalam 한국응용곤충학회 2019 Journal of Asia-Pacific Entomology Vol.22 No.2

Susceptibility of Asian corn borer (ACB), Ostrinia furnacalis (Guenée) to Bacillus thuringiensis (Bt) Cry1Ab protein was studied between 2015 and 2016 with 11 ACB populations, collected from various geographical regions in Vietnam. A concentration range of Cry1Ab from 0.20 to 26.10 ng/cm 2 of diet was evaluated against F 1 ACB neonates using diet surface-overlay bioassays. Mortality data was recorded daily until seven days after infestation. Growth inhibition was recorded at the end of seven days. The median lethal concentration (LC 50 ) varied ≈3-fold among the different populations, ranging from 0.58 to 1.83 ng/cm 2 of diet with an overall mean of 0.86 ng/cm 2 of diet. Even the lowest concentration of 0.20 ng/cm 2 caused 73.53% growth inhibition. > 90% growth inhibition was achieved at 0.82 ng/cm 2 or higher concentrations. The results reflect natural variation in Bt susceptibility among ACB populations rather than variation caused by prior exposure to selection pressures. LC 99 value (17.26 ng/cm 2 ) was generated by pooling mortality data across different populations. The upper fiducial limit of LC 99 (24.38 ng/cm 2 ) could be a potential diagnostic dose for future resistance monitoring programs. The findings from this study suggest that ACB populations in Vietnam are highly susceptible to Cry1Ab protein. This is the first report of Cry1Ab susceptibility of different ACB populations in Vietnam and will serve as a baseline for future resistance monitoring work.