| 1. |
- Phu, Vu Dinh, et al.
(författare)
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Ventilator-associated respiratory infection in a resource-restricted setting: impact and etiology
- 2017
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Ingår i: Journal of Intensive Care. - : BioMed Central (BMC). - 2052-0492. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Ventilator-associated respiratory infection (VARI) is a significant problem in resource-restricted intensive care units (ICUs), but differences in casemix and etiology means VARI in resource-restricted ICUs may be different from that found in resource-rich units. Data from these settings are vital to plan preventative interventions and assess their cost-effectiveness, but few are available.
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| 2. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - 2050-084X. ; 5
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Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.522.7) and 16.5 cm (13.319.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 3. |
- Bentham, James, et al.
(författare)
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A century of trends in adult human height
- 2016
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Ingår i: eLIFE. - : eLife Sciences Publications Ltd. - 2050-084X. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5–22.7) and 16.5 cm (13.3– 19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8– 144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries.
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| 4. |
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| 5. |
- Son, Dang Ngoc, et al.
(författare)
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A novel design and fabrication of self-heated In2O3 nanowire gas sensor on for ethanol detection
- 2022
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Ingår i: Sensors and Actuators A-Physical. - : Elsevier. - 0924-4247 .- 1873-3069. ; 345
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Tidskriftsartikel (refereegranskat)abstract
- Many attempts have been made on the design and fabrication of low-power consumption gas sensor for application on the Internet of Things and portable devices. The performance of gas sensors includes sensitivity, selectivity, and power consumption, which are strongly dependent on the configuration of the device such as the gap size between two electrodes, the sensing material, and operation principle. Here, self-heated In2O3 nanowire-based gas sensors were designed and fabricated by on-chip growth technique via thermal evaporation to work at room temperature. The effect of electrode gap (10-40 mu m) on the power consumption and gas sensing performance of the In2O3 nanowire sensors was studied. With the large gap of 40 mu m, the sensor exhibited excellent sensing characteristics of low power consumption (1.06 mW) with ability to detect ethanol gas down to 20 ppm effectively. We also examined the role of nanowire conductivity in the performance of the self-heated sensor in the detection of reducing gas. The sensor demonstrated rapid response and recovery times of less than a minute, exceptional stability, and remarkable recovery.
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| 6. |
- Phu, Vu Dinh, et al.
(författare)
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Burden of Hospital Acquired Infections and Antimicrobial Use in Vietnamese Adult Intensive Care Units
- 2016
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Ingår i: PLOS ONE. - : PUBLIC LIBRARY SCIENCE. - 1932-6203. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- Background Vietnam is a lower middle-income country with no national surveillance system for hospital-acquired infections (HAIs). We assessed the prevalence of hospital-acquired infections and antimicrobial use in adult intensive care units (ICUs) across Vietnam. Methods Monthly repeated point prevalence surveys were systematically conducted to assess HAI prevalence and antimicrobial use in 15 adult ICUs across Vietnam. Adults admitted to participating ICUs before 08: 00 a.m. on the survey day were included. Results Among 3287 patients enrolled, the HAI prevalence was 29.5% (965/3266 patients, 21 missing). Pneumonia accounted for 79.4% (804/1012) of HAIs Most HAIs (84.5% [855/1012]) were acquired in the survey hospital with 42.5% (363/855) acquired prior to ICU admission and 57.5% (492/855) developed during ICU admission. In multivariate analysis, the strongest risk factors for HAI acquired in ICU were: intubation (OR 2.76), urinary catheter (OR 2.12), no involvement of a family member in patient care (OR 1.94), and surgery after admission (OR 1.66). 726 bacterial isolates were cultured from 622/1012 HAIs, most frequently Acinetobacter baumannii (177/726 [24.4%]), Pseudomonas aeruginosa (100/726 [13.8%]), and Klebsiella pneumoniae (84/726 [11.6%]), with carbapenem resistance rates of 89.2%, 55.7%, and 14.9% respectively. Antimicrobials were prescribed for 84.8% (2787/ 3287) patients, with 73.7% of patients receiving two or more. The most common antimicrobial groups were third generation cephalosporins, fluoroquinolones, and carbapenems (20.1%, 19.4%, and 14.1% of total antimicrobials, respectively). Conclusion A high prevalence of HAIs was observed, mainly caused by Gram-negative bacteria with high carbapenem resistance rates. This in combination with a high rate of antimicrobial use illustrates the urgent need to improve rational antimicrobial use and infection control efforts.
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| 7. |
- Nguyen, Quang Linh, et al.
(författare)
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Vascular PDGFR-alpha protects against BBB dysfunction after stroke in mice
- 2021
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Ingår i: Angiogenesis. - : Springer. - 0969-6970 .- 1573-7209. ; 24, s. 35-46
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Tidskriftsartikel (refereegranskat)abstract
- Blood-brain barrier (BBB) dysfunction underlies the pathogenesis of many neurological diseases. Platelet-derived growth factor receptor-alpha (PDGFR alpha) induces hemorrhagic transformation (HT) downstream of tissue plasminogen activator in thrombolytic therapy of acute stroke. Thus, PDGFs are attractive therapeutic targets for BBB dysfunction. In the present study, we examined the role of PDGF signaling in the process of tissue remodeling after middle cerebral arterial occlusion (MCAO) in mice. Firstly, we found that imatinib increased lesion size after permanent MCAO in wild-type mice. Moreover, imatinib-induced HT only when administrated in the subacute phase of MCAO, but not in the acute phase. Secondly, we generated genetically mutated mice (C-KO mice) that showed decreased expression of perivascular PDGFR alpha. Additionally, transient MCAO experiments were performed in these mice. We found that the ischemic lesion size was not affected; however, the recruitment of PDGFR alpha/type I collagen-expressing perivascular cells was significantly downregulated, and HT and IgG leakage was augmented only in the subacute phase of stroke in C-KO mice. In both experiments, we found that the expression of tight junction proteins and PDGFR beta-expressing pericyte coverage was not significantly affected in imatinib-treated mice and in C-KO mice. The specific implication of PDGFR alpha signaling was suggestive of protective effects against BBB dysfunction during the subacute phase of stroke. Vascular TGF-beta 1 expression was downregulated in both imatinib-treated and C-KO mice, along with sustained levels of MMP9. Therefore, PDGFR alpha effects may be mediated by TGF-beta 1 which exerts potent protective effects in the BBB.
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| 8. |
- Zhou, Bin, et al.
(författare)
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Worldwide trends in diabetes since 1980: A pooled analysis of 751 population-based studies with 4.4 million participants
- 2016
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Ingår i: The Lancet. - : Elsevier B.V.. - 0140-6736 .- 1474-547X. ; 387:10027, s. 1513-1530
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Tidskriftsartikel (refereegranskat)abstract
- Background: One of the global targets for non-communicable diseases is to halt, by 2025, the rise in the age standardised adult prevalence of diabetes at its 2010 levels. We aimed to estimate worldwide trends in diabetes, how likely it is for countries to achieve the global target, and how changes in prevalence, together with population growth and ageing, are aff ecting the number of adults with diabetes.Methods: We pooled data from population-based studies that had collected data on diabetes through measurement of its biomarkers. We used a Bayesian hierarchical model to estimate trends in diabetes prevalence-defined as fasting plasma glucose of 7.0 mmol/L or higher, or history of diagnosis with diabetes, or use of insulin or oral hypoglycaemic drugs-in 200 countries and territories in 21 regions, by sex and from 1980 to 2014. We also calculated the posterior probability of meeting the global diabetes target if post-2000 trends continue.Findings: We used data from 751 studies including 4372000 adults from 146 of the 200 countries we make estimates for. Global age-standardised diabetes prevalence increased from 4.3% (95% credible interval 2.4-17.0) in 1980 to 9.0% (7.2-11.1) in 2014 in men, and from 5.0% (2.9-7.9) to 7.9% (6.4-9.7) in women. The number of adults with diabetes in the world increased from 108 million in 1980 to 422 million in 2014 (28.5% due to the rise in prevalence, 39.7% due to population growth and ageing, and 31.8% due to interaction of these two factors). Age-standardised adult diabetes prevalence in 2014 was lowest in northwestern Europe, and highest in Polynesia and Micronesia, at nearly 25%, followed by Melanesia and the Middle East and north Africa. Between 1980 and 2014 there was little change in age-standardised diabetes prevalence in adult women in continental western Europe, although crude prevalence rose because of ageing of the population. By contrast, age-standardised adult prevalence rose by 15 percentage points in men and women in Polynesia and Micronesia. In 2014, American Samoa had the highest national prevalence of diabetes (>30% in both sexes), with age-standardised adult prevalence also higher than 25% in some other islands in Polynesia and Micronesia. If post-2000 trends continue, the probability of meeting the global target of halting the rise in the prevalence of diabetes by 2025 at the 2010 level worldwide is lower than 1% for men and is 1% for women. Only nine countries for men and 29 countries for women, mostly in western Europe, have a 50% or higher probability of meeting the global target.Interpretation: Since 1980, age-standardised diabetes prevalence in adults has increased, or at best remained unchanged, in every country. Together with population growth and ageing, this rise has led to a near quadrupling of the number of adults with diabetes worldwide. The burden of diabetes, both in terms of prevalence and number of adults aff ected, has increased faster in low-income and middle-income countries than in high-income countries.
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| 9. |
- Duong, Quang Trung, et al.
(författare)
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Pairwise Error Probability of Distributed Space--Time Coding Employing Alamouti Scheme in Wireless Relays Networks
- 2009
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Ingår i: Wireless personal communications. - : Springer. - 0929-6212 .- 1572-834X. ; 51:2, s. 231-244
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, we analyze the pairwise error probability (PEP) of distributed space-time codes, in which the source and the relay generate Alamouti space--time code in a distributed fashion. We restrict our attention to the space-time code construction for Protocol III in [1]. In particular, we derive two closed-form approximations for PEP when the relay is either close to the destination or source and an upper bound for any position of the relay. Using the alternative definition of $Q$-function, we can express these PEPs in terms of finite integral whose integrand is composed of trigonometric functions. We further show that with only one relay assisted source-destination link, system still achieves diversity order of two, assuming single-antenna terminals. We also perform Monte-Carlo simulations to verify the analysis.
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| 10. |
- Nguyen, Ngoc Quang, et al.
(författare)
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Cardiovascular disease risk factor patterns and their implications for intervention strategies in Vietnam
- 2012
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Ingår i: International Journal of Hypertension. - : Hindawi Limited. - 2090-0384 .- 2090-0392.
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Tidskriftsartikel (refereegranskat)abstract
- Background. Data on cardiovascular disease risk factors (CVDRFs) in Vietnam are limited. This study explores the prevalence of each CVDRF and how they cluster to evaluate CVDRF burdens and potential prevention strategies. Methods. A cross-sectional survey in 2009 (2,130 adults) was done to collect data on behavioural CVDRF, anthropometry and blood pressure, lipidaemia profiles, and oral glucose tolerance tests. Four metabolic CVDRFs (hypertension, dyslipidaemia, diabetes, and obesity) and five behavioural CVDRFs (smoking, excessive alcohol intake, unhealthy diet, physical inactivity, and stress) were analysed to identify their prevalence, cluster patterns, and social predictors. Framingham scores were applied to estimate the global 10-year CVD risks and potential benefits of CVD prevention strategies. Results. The age-standardised prevalence of having at least 2/4 metabolic, 2/5 behavioural, or 4/9 major CVDRF was 28%, 27%, 13% in women and 32%, 62%, 34% in men. Within-individual clustering of metabolic factors was more common among older women and in urban areas. High overall CVD risk (≥20% over 10 years) identified 20% of men and 5% of women—especially at higher ages—who had coexisting CVDRF. Conclusion. Multiple CVDRFs were common in Vietnamese adults with different clustering patterns across sex/age groups. Tackling any single risk factor would not be efficient.
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| 11. |
- Nguyen, Ngoc Quang, et al.
(författare)
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Effectiveness of community-based comprehensive healthy lifestyle promotion on cardiovascular disease risk factors in a rural Vietnamese population : a quasi-experimental study
- 2012
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Ingår i: BMC Cardiovascular Disorders. - : Springer Science and Business Media LLC. - 1471-2261 .- 1471-2261. ; 12:article nr 56
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Tidskriftsartikel (refereegranskat)abstract
- Background: Health promotion is a key component for primary prevention of cardiovascular disease (CVD). This study evaluated the impact of healthy lifestyle promotion campaigns on CVD risk factors (CVDRF) in the general population in the context of a community-based programme on hypertension management. Methods: A quasi-experimental intervention study was carried out in two rural communes of Vietnam from 2006 to 2009. In the intervention commune, a hypertensive-targeted management programme integrated with a community-targeted health promotion was initiated, while no new programme, apart from conventional healthcare services, was provided in the reference commune. Health promotion campaigns focused on smoking cessation, reducing alcohol consumption, encouraging physical activity and reducing salty diets. Repeated cross-sectional surveys in local adult population aged 25 years and over were undertaken to assess changes in blood pressure (BP) and behavioural CVDRFs (smoking, alcohol consumption, physical inactivity and salty diet) in both communes before and after the 3-year intervention. Results: Overall 4,650 adults above 25 years old were surveyed, in four randomly independent samples covering both communes at baseline and after the 3-year intervention. Although physical inactivity and obesity increased over time in the intervention commune, there was a significant reduction in systolic and diastolic BP (3.3 and 4.7 mmHg in women versus 3.0 and 4.6 mmHg in men respectively) in the general population at the intervention commune. Health promotion reduced levels of salty diets but had insignificant impact on the prevalence of daily smoking or heavy alcohol consumption. Conclusion: Community-targeted healthy lifestyle promotion can significantly improve some CVDRFs in the general population in a rural area over a relatively short time span. Limited effects on a context-bound CVDRF like smoking suggested that higher intensity of intervention, a supportive environment or a gender approach are required to maximize the effectiveness and maintain the sustainability of the health intervention.
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| 12. |
- Nguyen, Ngoc Quang, et al.
(författare)
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Time trends in blood pressure, body mass index and smoking in the Vietnamese population : a meta-analysis from multiple cross-sectional surveys
- 2012
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 7:8, s. e42825-
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Data for trends in cardiovascular disease (CVD) risk factors are needed to set priorities and evaluate intervention programmes in the community. We estimated time trends in blood pressure ( BP), anthropometric variables and smoking in the Vietnamese population and highlighted the differences between men and women or between rural and urban areas.Methods: A dataset of 23,563 adults aged 25-74 from 5 cross-sectional surveys undertaken within Vietnam from 2001 to 2009 by the Vietnam National Heart Institute was used to estimate mean BP, weight, waist circumference (WC), body mass index (BMI), the prevalence of hypertension, adiposity or smoking, which were standardised to the national age structure of 2009. Multilevel mixed linear models were used to estimate annual changes in the variables of interest, adjusted by age, sex, residential area, with random variations for age and surveyed provinces.Findings: Among the adult population, the age-standardised mean systolic and diastolic BP increased by 0.8 and 0.3 mmHg in women, 1.1 and 0.4 mmHg in men, while the mean BMI increased by 0.1 kgm(-2) in women, 0.2 kgm(-2) in men per year. Consequently, the prevalence of hypertension and adiposity increased by 0.9 and 0.3% in women, 1.1 and 0.9% in men with similar time trends in both rural and urban areas, while smoking prevalence only increased in women by 0.3% per year. A U-shaped association was found between age-adjusted BP and BMI in both sexes and in both areas.Conclusions: From 2001 to 2009, mean BP, weight and WC significantly increased in the Vietnamese population, leading to an increased prevalence of hypertension and adiposity, suggesting the need for the development of multi-sectoral cost-effective population-based interventions to improve CVD management and prevention. The U-shaped relationship between BP and BMI highlighted the hypertension burden in the underweight population, which is usually neglected in CVD interventions.
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| 13. |
- Nguyen, Quang Ngoc, et al.
(författare)
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Implementing a hypertension management programme in a rural area : local approaches and experiences from Ba-Vi district, Vietnam
- 2011
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Ingår i: BMC Public Health. - : BioMed Central. - 1471-2458. ; 11, s. 325-
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Costly efforts have been invested to control and prevent cardiovascular diseases (CVD) and their risk factors but the ideal solutions for low resource settings remain unclear. This paper aims at summarising our approaches to implementing a programme on hypertension management in a rural commune of Vietnam. METHODS: In a rural commune, a programme has been implemented since 2006 to manage hypertensive people at the commune health station and to deliver health education on CVD risk factors to the entire community. An initial cross-sectional survey was used to screen for hypertensives who might enter the management programme. During 17 months of implementation, other people with hypertension were also followed up and treated. Data were collected from all individual medical records, including demographic factors, behavioural CVD risk factors, blood pressure levels, and number of check-ups. These data were analysed to identify factors relating to adherence to the management programme. RESULTS: Both top-down and bottom-up approaches were applied to implement a hypertension management programme. The programme was able to run independently at the commune health station after 17 months. During the implementation phase, 497 people were followed up with an overall regular follow-up of 65.6% and a dropout of 14.3%. Severity of hypertension and effectiveness of treatment were the main factors influencing the decision of people to adhere to the management programme, while being female, having several behavioural CVD risk factors or a history of chronic disease were the predictors for deviating from the programme. CONCLUSION: Our model showed the feasibility, applicability and future potential of a community-based model of comprehensive hypertension care in a low resource context using both top-down and bottom-up approaches to engage all involved partners. This success also highlighted the important roles of both local authorities and a cardiac care network, led by an outstanding cardiac referral centre.
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| 14. |
- Nguyen, Quang Ngoc, 1976-
(författare)
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Understanding and managing cardiovascular disease risk factors in Vietnam : integrating clinical and public health perspectives
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background: Vietnam, like other low-income countries, is facing an epidemic burden of cardiovascular disease risk factors (CVDRFs). The magnitude and directions of CVDRF progression are matters of uncertainty. Objectives: To describe the epidemiological progression of CVDRFs and the preventive effects of community lifestyle interventions, with reference to the differences in progression of CVDRF patterns between men and women. Methods: The study was conducted during 2001-2009 in nationally representative samples and in a local setting of rural areas of Ba-Vi district, Ha-Tay province. Both epidemiological and interventional approaches were applied: (i) a population-based cross-sectional survey of 2,130 people aged ≥25 years in Thai-Binh and Hanoi; (ii) an individual participant-level meta analysis of 23,563 people aged 24-74 years from multiple similar surveys in 9 provinces around Vietnam; (iii) a 17-month cohort study of 497 patients in a hypertension management programme; (iv) a quasi-experimental trial on community lifestyle promotion integrated with a hypertension management programme, evaluated by surveys of 4,645 people in both intervention and reference communes before and after a 3-year intervention. Main findings: (i) in the general adult population ≥25 years, CVDRFs were common, often clustered within individuals, and increased with age; (ii) the Vietnamese population is facing a growing epidemic of CVDRFs, which are generally not well managed; (iii) it is possible to launch a community intervention in low-resource settings within the scope of a commune-based patient-targeted programme on hypertension management; (iv) community health intervention with comprehensive healthy lifestyle promotion improves blood pressure and some behavioural CVDRFs. Conclusion: Alarming increases in CVDRFs in the general population need comprehensive multi-level prevention strategies, which combine both individual high-risk and population health approaches. The commune-based hypertension-centred management programmes integrated with community health promotion are the initial but essential steps towards comprehensive and effective management of CVDRFs and should be part of an integrated and co-ordinated national program on the prevention and control of chronic diseases in low-resource settings like Vietnam.
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| 15. |
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| 16. |
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| 17. |
- Trung, Hieu Tran, et al.
(författare)
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Anti-inflammatory and Antiphytopathogenic Fungal Activity of 2,3-seco-Tirucallane Triterpenoids Meliadubins A and B from Melia dubia Cav. Barks with ChemGPS-NP and In Silico Prediction
- 2023
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 8:40, s. 37116-37127
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Tidskriftsartikel (refereegranskat)abstract
- Two new rearranged 2,3-seco-tirucallane triterpenoids, meliadubins A (1) and B (2), along with four known compounds, 3-6, were isolated from the barks of Melia dubia Cav. Compound 2 exhibited a significant inflammatory inhibition effect toward superoxide anion generation in human neutrophils (EC50 at 5.54 +/- 0.36 mu M). It bound to active sites of a human inducible nitric oxide synthase (3E7G) through interactions with the residues of GLU377 and PRO350, which may benefit in reducing the neutrophilic inflammation effect. The ChemGPS-NP interpretation combined with bioactivity assay and in silico prediction results suggested 2 to be an agent for targeting iNOS with different mechanisms as compared to a selected set of current approved drugs. Moreover, compounds 1 and 2 showed remarkable inhibition against the rice pathogenic fungus Magnaporthe oryzae in a dose-dependent manner with IC50 values of 137.20 +/- 9.55 and 182.50 +/- 18.27 mu M, respectively. Both 1 and 2 displayed interactions with the residue of TYR223, a key active site of trihydroxynaphthalene reductase (1YBV). The interpretation of 1 and 2 in the ChemGPS-NP physical-chemical property space indicated that both compounds are quite different compared to all members of a selected set of reference compounds. In light of demonstrated biological activity and in silico prediction experiments, both compounds possibly exhibited activity against phytopathogenic fungi via a novel mode of action.
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| 18. |
- Chung, Sunjae, et al.
(författare)
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Magnetic droplet solitons in all-perpendicular nano-contact spin torque oscillators
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Annan publikation (populärvet., debatt m.m.)abstract
- Spin-torque-generated magnetic droplets are nontopological solitons that have both dynamic and static characteristics. Although theoretical studies of these droplets originally dealt with an all-perpendicular magnetic system, all experimental demonstrations have so far relied on orthogonal spin valve structures that require a rather strong magnetic field to nucleate the droplet. Here, for the first time, we show the nucleation and sustained operation of magnetic droplets under a low magnetic field using nanocontact spin-torque oscillators (NC-STO), both the free Co/Ni and fixed Co/Pd multilayers of which have strong perpendicular magnetic anisotropy. Droplet nucleation is observed as a change in the NC-STO resistance and the appearance of significant broadband microwave signal generation below 1 GHz. We also observe another important phenomenon in which the nucleated magnetic droplet can transform into a skyrmionic nanobubble in the low-field regime. Both magnetic droplet solitons and skyrmionic nanobubbles have been studied in detail using micromagnetic simulation.
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| 19. |
- Ho-Quang, Truong, 1989, et al.
(författare)
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Role stereotypes in software designs and their evolution
- 2022
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Ingår i: Journal of Systems and Software. - : Elsevier BV. - 0164-1212. ; 189
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Tidskriftsartikel (refereegranskat)abstract
- Role stereotypes are abstract characterisations of the responsibilities of the building blocks of software applications. The role a class plays within a software system reflects its design intention. Wirfs-Brock introduced the following six role stereotypes: Information Holder, which knows information, Structurer, which maintains object relationships, Service Provider, which offers computing services, Coordinator, which delegates tasks to others, Controller, which directs other's actions, and Interfacer, which transforms information. Knowledge about class role stereotypes can help various software development and maintenance tasks, such as program understanding, program summarisation, and quality assurance. This paper presents an automated machine learning-based approach for classifying the role-stereotype of classes in Java projects. We analyse this approach's performance against a manually labelled ground truth for three open source projects that contain 1,500+ Java classes altogether. The contributions of this paper include: (i) a machine learning (ML) approach to address the problem of automatically inferring role-stereotypes of classes in Object-Oriented Programming Languages, (ii) the manually labelled ground truth, (iii) an evaluation of the performance of the classifier, (iv) an evaluation of the generalisability of the approach, and (v) an illustration of new uses of role-stereotypes. The evaluation shows that the Random Forest algorithm yields the best classification performance. We find, however, that the performance of the ML-classifier varies a lot for different role stereotypes. In particular, its performance degrades when classifying rarer stereotypes. Among the 23 features that we study, features related to the classes’ collaboration characteristics and complexity stand out as the best discriminants of role stereotypes.
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| 20. |
- Le, Quang Tuan, 1976-, et al.
(författare)
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Bias dependence of parallel spin torque in all-perpendicular magnetic tunnel junction nanodevices
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Annan publikation (populärvet., debatt m.m.)abstract
- We performed spin-torque ferromagnetic resonance measurements on spin-torque oscillators based on CoFeB/MgO/CoFeB magnetic tunnel junctions (MTJs), with both free and fixed layers having perpendicular magnetic anisotropy, under the application of an in-plane field. A dc current between near-zero and -250 $\mu{A}$ was introduced to investigate the influence of spin-transfer torque effects on the asymmetric and symmetric components of the output voltage. Both components showed a minimum at a misalignment of about 30$^\circ$ between the magnetization of the two CoFeB layers, indicating a strong electric-field effect. We also found that the bias dependence of the spin-torque terms is in contrast to that of in-plane anisotropy CoFeB MTJs.
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| 21. |
- Le, Quang Tuan, 1976-, et al.
(författare)
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Ultra-high frequency tunability in low-current and low-field spin-torque oscillators based on perpendicular magnetic tunnel junctions
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Annan publikation (populärvet., debatt m.m.)abstract
- We demonstrate ultra-high frequency tunability of up to 4.4 GHz/mA, and low threshold currents of about -21 $\mu$A, in spin-torque oscillators based on CoFeB/MgO/CoFeB magnetic tunnel junctions, in which both free and fixed layers have perpendicular magnetic anisotropy (PMA). By using different thicknesses of the two CoFeB layers, their individual PMA strengths can be tailored to achieve significant relative misalignment of their respective magnetizations in moderate in-plane fields. We observe a broad maximum in both the device resistance and the generated microwave power around maximum misalignment. Maximum frequency tunability is observed at low-to-moderate fields and decrease rapidly after maximum misalignment.
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| 22. |
- Nguyen, Thi Ngoc Anh, et al.
(författare)
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Investigation of the Tunability of the Spin Configuration Inside Exchange Coupled Springs of Hard/Soft Magnets
- 2014
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Ingår i: IEEE transactions on magnetics. - 0018-9464 .- 1941-0069. ; 50:6, s. 2004906-
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Tidskriftsartikel (refereegranskat)abstract
- Magnetic multilayer (ML) structures comprising a perpendicular magnetic anisotropy (PMA) layer coupled to an in-plane magnetic anisotropy (IMA) layer are promising materials for zero/low field operating spin-torque oscillators and bit patterned recording media. The magnetization tilt angle can be easily tuned by varying the IMA layer thickness due to the competition between PMA and IMA layers. To explore the underlying magnetization reversal mechanism and to further understand the control of tilt angle and uniformity of the magnetization, the IMA (NiFe, Co, and CoFeB)/PMA (Co/Pd MLs) exchange spring systems are systematically studied. Experimental data obtained from magnetometry show good agreement with 1-D micromagnetic simulations, allowing us to design tunable exchange coupled spring as a function of IMA thickness.
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| 23. |
- Pham, Son Thai, et al.
(författare)
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Prevalence, awareness, treatment and control of hypertension in Vietnam : results from a national survey
- 2012
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Ingår i: Journal of Human Hypertension. - : Nature Publishing Group. - 0950-9240 .- 1476-5527. ; 26, s. 268-280
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to estimate mean blood pressure (BP), prevalence of hypertension (defined as BP 140/90 mm Hg) and its awareness, treatment and control in the Vietnamese adult population. This cross-sectional survey took place in eight Vietnamese provinces and cities. Multi-stage stratified sampling was used to select 9832 participants from the general population aged 25 years and over. Trained observers obtained two or three BP measurements from each person, using an automatic sphygmomanometer. Information on socio-geographical factors and anti-hypertensive medications was obtained using a standard questionnaire. The overall prevalence of hypertension was 25.1%, 28.3% in men and 23.1% in women. Among hypertensives, 48.4% were aware of their elevated BP, 29.6% had treatment and 10.7% achieved targeted BP control (<140/90 mm Hg). Among hypertensive aware, 61.1% had treatment, and among hypertensive treated, 36.3% had well control. Hypertension increased with age in both men and women. The hypertension was significantly higher in urban than in rural areas (32.7 vs 17.3%, P<0.001). Hypertension is a major and increasing public health problem in Vietnam. Prevalence among adults is high, whereas the proportions of hypertensives aware, treated and controlled were unacceptably low. These results imply an urgent need to develop national strategies to improve prevention and control of hypertension in Vietnam.
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