This paper compares centralized and distributed methods to solve the power minimization problem w... more This paper compares centralized and distributed methods to solve the power minimization problem with quality-of-service (QoS) constraints in the downlink (DL) of multi-cell Massive multiple-input multiple-output (MIMO) systems. In particular, we study the computational complexity, number of parameters that need to be exchanged between base stations (BSs), and the convergence of iterative implementations. Although a distributed implementation based on dual decomposition (which only requires statistical channel knowledge at each BS) typically converges to the global optimum after a few iterations, many parameters need to be exchanged to reach convergence.
Burns : journal of the International Society for Burn Injuries, Jan 17, 2018
The injury severity score considers burn size and inhalation injury in estimating overall anatomi... more The injury severity score considers burn size and inhalation injury in estimating overall anatomical injury severity. Models that adjust for injury severity score in addition to total burn size and inhalation injury may therefore be double counting the risk from these individual burn characteristics, and obscuring (or overemphasizing) the contribution of risk from each source. The primary aim of this study was to compare differences in the estimated mortality risk of burn trauma using the traditional injury severity score (ISS) calculation and the non-burn injury severity score (NBISS) to examine how separating out the risk attributable to the burn injury versus other trauma changes the interpretation and clinical assessment. Among U.S. casualties sustaining burns during combat operations in Iraq and Afghanistan from March 2003 to October 2013, we performed a retrospective cohort study. Unadjusted, adjusted, and weighted Cox proportional hazards models were performed to estimate the...
Medical & biological engineering & computing, 2018
Vibroarthrography is a radiation-free and inexpensive method of assessing the condition of knee c... more Vibroarthrography is a radiation-free and inexpensive method of assessing the condition of knee cartilage damage during extension-flexion movements. Acoustic sensors were placed on the patella and medial tibial plateau (two accelerometers) as well as on the lateral tibial plateau (a piezoelectric disk) to measure the structure-borne noise in 59 asymptomatic knees and 40 knees with osteoarthritis. After semi-automatic segmentation of the acoustic signals, frequency features were generated for the extension as well as the flexion phase. We propose simple and robust features based on relative high-frequency components. The normalized nature of these frequency features makes them insusceptible to influences on the signal gain, such as attenuation by fat tissue and variance in acoustic coupling. We analyzed their ability to serve as classification features for detection of knee osteoarthritis, including the effect of normalization and the effect of combining frequency features of all thr...
Three cycloartane-type triterpene glycosides (anopanins A-C), together with three known monoacyld... more Three cycloartane-type triterpene glycosides (anopanins A-C), together with three known monoacyldigalactosylglycerols gingerglycolipids A-C and (2S)-1-O-palmitoyl-3-O-[α-d-galactopyranosyl-(1→6)-β-d-galactopyranosyl]-sn-glycerol, were isolated from the aerial parts of Anodendron paniculatum collected in Viet Nam. The chemical structures of the present compounds were elucidated by means of 1D and 2D NMR and HRESIMS spectroscopy, and by comparing to the reported data in the literature. These compounds did not show significant growth inhibitory activities (IC50 > 100 μg/mL) against the tested cancer cell lines LU-1 (lung adenocarcinoma), KB (epidermoid carcinoma), Hep-G2 (hepatoma cancer), MKN-7 (stomach cancer), and SW-480 (colon adenocarcinoma).
Co-payment for methadone maintenance treatment (MMT) services is a strategy to ensure the financi... more Co-payment for methadone maintenance treatment (MMT) services is a strategy to ensure the financial sustainability of the HIV/AIDS programs in Vietnam. In this study, we examined health services utilization and expenditure among MMT patients, and further explored factors associated with catastrophic health expenditure among affected households. A multi-site cross-sectional study was conducted among 1016 patients in two epicentres: Hanoi and Nam Dinh province in 2013. Overall, 8.2% and 28.7% respondents used inpatient and outpatient health care services in the past 12 months apart from receiving MMT. There were 12.8% respondents experiencing catastrophic health expenditure given MMT is provided free-of-charge, otherwise 63.5% patients would suffer from health care costs. MMT integrated with general health or HIV services may encourage health care services utilization of patients. Patients, who were single, lived in the rural, had inpatient care and reported problems in Mobility were more likely to experience catastrophic health expenditure than other patient groups. The health care costs are still financially burden to many drug users and remained over the course of MMT that implies the necessity of continuous supports from the program. Scaling-up and decentralizing integrated MMT clinics together with economic empowerments for treated drug users and their families should be prioritized in Vietnam.
2015 Seventh International Conference on Knowledge and Systems Engineering (KSE), 2015
Text classification is a very important task due to the huge amount of electronic documents. One ... more Text classification is a very important task due to the huge amount of electronic documents. One of the main challenges for text classification is the high dimensionality of feature spaces. There have been extensive studies on feature selections for English text classification. However, not many works have been studied on Vietnamese text classification. This paper evaluates the performances of the three widely used feature selection methods [2][6][10]: the Chi-square (CHI), the Information Gain (IG), and the Document Frequency (DF). Based on the evaluation, we propose a hybrid feature selection method, called SIGCHI, which combines the Chi-square and the Information Gain feature selection methods. Our experimental results showed that the proposed method performs significantly better than the other methods. The accuracy of SIGCHI method is up to 15.03% higher than the one of CHI method, up to 18.65% higher than the one of IG method, and up to 27.72% higher than the one of DF method, respectively.
2013 10th International Conference on the European Energy Market (EEM), 2013
ABSTRACT In this paper, a mathematical model is proposed for optimization of the portfolio of an ... more ABSTRACT In this paper, a mathematical model is proposed for optimization of the portfolio of an electricity retailer in the forward and spot markets considering flexibility offered by electric vehicles (EV). The model provides a guideline to the elec- tricity retailer for aggregated scheduling of EV battery charging, contracting of power in the forward market and setting of retail prices for customers under fixed and variable price electricity retail contracts. The objective of the model is to maximize the retailer’s expected profit. A stochastic programming approach is used to account for the uncertainties associated with spot price, customers’ demand and EV demand. The model is applied to a case study using data from the Nordic electricity markets, future scenarios for EVs in Sweden and an electricity retailer in Sweden. Results indicate that cost savings from flexibility of EV demand would increase with increasing EV penetration level and the number of customers with variable price contracts as opposed to fixed price contracts. It is also found that the retailer’s expected profits would increase with a greater share of variable price contracts.
The implementation of multilayer optics for the compression and delivery of few-cycle femtosecond... more The implementation of multilayer optics for the compression and delivery of few-cycle femtosecond pulses will be discussed in the case of several cutting-edge applications.
This paper compares centralized and distributed methods to solve the power minimization problem w... more This paper compares centralized and distributed methods to solve the power minimization problem with quality-of-service (QoS) constraints in the downlink (DL) of multi-cell Massive multiple-input multiple-output (MIMO) systems. In particular, we study the computational complexity, number of parameters that need to be exchanged between base stations (BSs), and the convergence of iterative implementations. Although a distributed implementation based on dual decomposition (which only requires statistical channel knowledge at each BS) typically converges to the global optimum after a few iterations, many parameters need to be exchanged to reach convergence.
Burns : journal of the International Society for Burn Injuries, Jan 17, 2018
The injury severity score considers burn size and inhalation injury in estimating overall anatomi... more The injury severity score considers burn size and inhalation injury in estimating overall anatomical injury severity. Models that adjust for injury severity score in addition to total burn size and inhalation injury may therefore be double counting the risk from these individual burn characteristics, and obscuring (or overemphasizing) the contribution of risk from each source. The primary aim of this study was to compare differences in the estimated mortality risk of burn trauma using the traditional injury severity score (ISS) calculation and the non-burn injury severity score (NBISS) to examine how separating out the risk attributable to the burn injury versus other trauma changes the interpretation and clinical assessment. Among U.S. casualties sustaining burns during combat operations in Iraq and Afghanistan from March 2003 to October 2013, we performed a retrospective cohort study. Unadjusted, adjusted, and weighted Cox proportional hazards models were performed to estimate the...
Medical & biological engineering & computing, 2018
Vibroarthrography is a radiation-free and inexpensive method of assessing the condition of knee c... more Vibroarthrography is a radiation-free and inexpensive method of assessing the condition of knee cartilage damage during extension-flexion movements. Acoustic sensors were placed on the patella and medial tibial plateau (two accelerometers) as well as on the lateral tibial plateau (a piezoelectric disk) to measure the structure-borne noise in 59 asymptomatic knees and 40 knees with osteoarthritis. After semi-automatic segmentation of the acoustic signals, frequency features were generated for the extension as well as the flexion phase. We propose simple and robust features based on relative high-frequency components. The normalized nature of these frequency features makes them insusceptible to influences on the signal gain, such as attenuation by fat tissue and variance in acoustic coupling. We analyzed their ability to serve as classification features for detection of knee osteoarthritis, including the effect of normalization and the effect of combining frequency features of all thr...
Three cycloartane-type triterpene glycosides (anopanins A-C), together with three known monoacyld... more Three cycloartane-type triterpene glycosides (anopanins A-C), together with three known monoacyldigalactosylglycerols gingerglycolipids A-C and (2S)-1-O-palmitoyl-3-O-[α-d-galactopyranosyl-(1→6)-β-d-galactopyranosyl]-sn-glycerol, were isolated from the aerial parts of Anodendron paniculatum collected in Viet Nam. The chemical structures of the present compounds were elucidated by means of 1D and 2D NMR and HRESIMS spectroscopy, and by comparing to the reported data in the literature. These compounds did not show significant growth inhibitory activities (IC50 > 100 μg/mL) against the tested cancer cell lines LU-1 (lung adenocarcinoma), KB (epidermoid carcinoma), Hep-G2 (hepatoma cancer), MKN-7 (stomach cancer), and SW-480 (colon adenocarcinoma).
Co-payment for methadone maintenance treatment (MMT) services is a strategy to ensure the financi... more Co-payment for methadone maintenance treatment (MMT) services is a strategy to ensure the financial sustainability of the HIV/AIDS programs in Vietnam. In this study, we examined health services utilization and expenditure among MMT patients, and further explored factors associated with catastrophic health expenditure among affected households. A multi-site cross-sectional study was conducted among 1016 patients in two epicentres: Hanoi and Nam Dinh province in 2013. Overall, 8.2% and 28.7% respondents used inpatient and outpatient health care services in the past 12 months apart from receiving MMT. There were 12.8% respondents experiencing catastrophic health expenditure given MMT is provided free-of-charge, otherwise 63.5% patients would suffer from health care costs. MMT integrated with general health or HIV services may encourage health care services utilization of patients. Patients, who were single, lived in the rural, had inpatient care and reported problems in Mobility were more likely to experience catastrophic health expenditure than other patient groups. The health care costs are still financially burden to many drug users and remained over the course of MMT that implies the necessity of continuous supports from the program. Scaling-up and decentralizing integrated MMT clinics together with economic empowerments for treated drug users and their families should be prioritized in Vietnam.
2015 Seventh International Conference on Knowledge and Systems Engineering (KSE), 2015
Text classification is a very important task due to the huge amount of electronic documents. One ... more Text classification is a very important task due to the huge amount of electronic documents. One of the main challenges for text classification is the high dimensionality of feature spaces. There have been extensive studies on feature selections for English text classification. However, not many works have been studied on Vietnamese text classification. This paper evaluates the performances of the three widely used feature selection methods [2][6][10]: the Chi-square (CHI), the Information Gain (IG), and the Document Frequency (DF). Based on the evaluation, we propose a hybrid feature selection method, called SIGCHI, which combines the Chi-square and the Information Gain feature selection methods. Our experimental results showed that the proposed method performs significantly better than the other methods. The accuracy of SIGCHI method is up to 15.03% higher than the one of CHI method, up to 18.65% higher than the one of IG method, and up to 27.72% higher than the one of DF method, respectively.
2013 10th International Conference on the European Energy Market (EEM), 2013
ABSTRACT In this paper, a mathematical model is proposed for optimization of the portfolio of an ... more ABSTRACT In this paper, a mathematical model is proposed for optimization of the portfolio of an electricity retailer in the forward and spot markets considering flexibility offered by electric vehicles (EV). The model provides a guideline to the elec- tricity retailer for aggregated scheduling of EV battery charging, contracting of power in the forward market and setting of retail prices for customers under fixed and variable price electricity retail contracts. The objective of the model is to maximize the retailer’s expected profit. A stochastic programming approach is used to account for the uncertainties associated with spot price, customers’ demand and EV demand. The model is applied to a case study using data from the Nordic electricity markets, future scenarios for EVs in Sweden and an electricity retailer in Sweden. Results indicate that cost savings from flexibility of EV demand would increase with increasing EV penetration level and the number of customers with variable price contracts as opposed to fixed price contracts. It is also found that the retailer’s expected profits would increase with a greater share of variable price contracts.
The implementation of multilayer optics for the compression and delivery of few-cycle femtosecond... more The implementation of multilayer optics for the compression and delivery of few-cycle femtosecond pulses will be discussed in the case of several cutting-edge applications.
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