Modeling the Linux page cache for accurate simulation of data-intensive applications

The emergence of Big Data in recent years has led to a growing need in data processing and an increasing number of data intensive applications. Processing and storage of massive amounts of data require large-scale solutions and thus must data-intensive applications be executed on infrastructures such as cloud or High Performance Computing (HPC) clusters. Although there are advancements of hardware/software stack that enable larger computing platforms, some relevant challenges remain in resource management, performance, scheduling, scalability, etc. As a result, there is an increasing demand for optimizing and quantifying performance when executing data-intensive applications on those platforms. While infrastructures with sufficient computing power and storage capacity are available, the I/O performance on disks remains a bottleneck. To tackle this problem, apart from hardware improvements, the Linux page cache is an efficient architectural approach to reduce I/O overheads, but few experimental studies of its interactions with Big Data applications exist, partly due to limitations of real-world experiments. Simulation is a popular approach to address these issues, however, existing simulation frameworks do not simulate page caching fully, or even at all. As a result, simulation-based performance studies of data-intensive applications lead to inaccurate results. This thesis proposes an I/O simulation model that captures the key features of the Linux page cache. We have implemented this model as part of the WRENCH workflow simulation framework, which itself builds on the popular SimGrid distributed systems simulation framework. Our model and its implementation enable the simulation of both single-threaded and multithreaded applications, and of both writeback and writethrough caches for local or network-based filesystems. We evaluate the accuracy of our model in different conditions, including sequential and concurrent applications, as well as local and remote I/Os. The results show that our page cache model reduces the simulation error by up to an order of magnitude when compared to state-of-the-art, cacheless simulations

Analyzing the Sea Weather Effects to the Ship Maneuvering in Vietnam’s Sea from BinhThuan Province to Ca Mau Province Based on Fuzzy Control Method

Vietnam is located in the tropical monsoon climate, so there are many storms affecting the marine environment each year. However, Vietnam’s sea also has distinct characteristics due to the continental shelf factors, salinity, sea currents and viscosity water. In this paper, the sea weather effects to the ship in the sea area from BinhThuan province to Ca Mau province are analyzed. Specifically, wave, wind and current which are the three main factors affecting the safety of ship are thoroughly examined. Importantly, the survey parameters have been built from the actual operating environment. In addition, maintaining the stability of dynamic positioning system in Vietnam weather conditions is the main point of this study

An Application of Vector Autoregressive Model for Analyzing the Impact of Weather And Nearby Traffic Flow On The Traffic Volume

This paper aims to predict the traffic flow at one road segment based on nearby traffic volume and weather conditions. Our team also discover the impact of weather conditions and nearby traffic volume on the traffic flow at a target point. The analysis results will help solve the problem of traffic flow prediction and develop an optimal transport network with efficient traffic movement and minimal traffic congestion. Hourly historical weather and traffic flow data are selected to solve this problem. This paper uses model VAR(36) with time trend and constant to train the dataset and forecast. With an RMSE of 565.0768111 on average, the model is considered appropriate although some statistical tests implies that the residuals are unstable and non-normal. Also, this paper points out some variables that are not useful in forecasting, which helps simplify the data-collecting process when building the forecasting system.Comment: International Conference on Computing and Communication Technologies (RIVF2022

Modelling the Vietnamese Economy. ESRI WP526. February 2016

This paper considers the factors determining the long-run behaviour of the Vietnamese economy. Using a macro-economic model of the Vietnamese economy it considers some of the factors that have contributed to growth over the last decade and also some of the policy options for the rest of the decade

A RESEARCH ON MULTI-OBJECTIVE OPTIMIZATION OF THE GRINDING PROCESS USING SEGMENTED GRINDING WHEEL BY TAGUCHI-DEAR METHOD

In this study, the mutil-objective optimization was applied for the surface grinding process of SAE420 steel. The aluminum oxide grinding wheels that were grooved by 15 grooves, 18 grooves, and 20 grooves were used in the experimental process. The Taguchi method was applied to design the experimental matrix. Four input parameters that were chosen for each experiment were the number of grooves in cylinder surface of grinding wheel, workpiece velocity, feed rate, and cutting depth. Four output parameters that were measured for each experimental were the machining surface roughness, the system vibrations in the three directions (X, Y, Z). The DEAR technique was applied to determine the values of the input parameters to obtaine the minimum values of machining surface roughness and vibrations in three directions. By using this technique, the optimum values of grinding wheel groove number, workpiece velocity, feed-rate, cutting depth were 18 grooves, 15 m/min, 2 mm/stroke, and 0.005 mm, respectively. The verified experimental was performed by using the optimum values of input parameters. The validation results of surface roughness and vibrations in X, Y, Z directions were 0.826 (µm), 0.531 (µm), 0.549 (µm), and 0. 646 (µm), respectively. These results were great improved in comparing to the normal experimental results. Taguchi method and DEAR technique can be applied to improve the quality of grinding surface and reduce the vibrations of the technology system to restrain the increasing of the cutting forces in the grinding process. Finally, the research direction was also proposed in this stud

An efficient adaptive fuzzy hierarchical sliding mode control strategy for 6 degrees of freedom overhead crane

The paper proposes a new approach to efficiently control a three-dimensional overhead crane with 6 degrees of freedom (DoF). Most of the works proposing a control law for a gantry crane assume that it has five output variables, including three positions of the trolley, bridge, and pulley and two swing angles of the hoisting cable. In fact, the elasticity of the hoisting cable, which causes oscillation in the cable direction, is not fully incorporated into the model yet. Therefore, our work considers that six under-actuated outputs exist in a crane system. To design an efficient controller for the 6 DoF crane, it first employs the hierarchical sliding mode control approach, which not only guarantees stability but also minimizes the sway and oscillation of the overhead crane when it transports a payload to a desired location. Moreover, the unknown and uncertain parameters of the system caused by its actuator nonlinearity and external disturbances are adaptively estimated and inferred by utilizing the fuzzy inference rule mechanism, which results in efficient operations of the crane in real time. More importantly, stabilization of the crane controlled by the proposed algorithm is theoretically proved by the use of the Lyapunov function. The proposed control approach was implemented in a synthetic environment for the extensive evaluation, where the obtained results demonstrate its effectiveness. © 2022 by the authors. Licensee MDPI, Basel, Switzerland

Challenges and Solutions for Ride-Hailing Motorbike Drivers in Vietnam: An Analysis of Working Conditions and Health

In the digital age, ride-hailing motorbike services have become an indispensable part of the urban transportation system in Vietnam, attracting thousands of workers with their flexibility and income potential. However, occupation also poses numerous health and safety challenges. The job requires long working hours, exposure to harsh weather conditions, and highly competitive pressure, leading to physical and mental health issues such as muscle pain, fatigue, and stress. This research article employs a survey method to collect data from ride-hailing motorbike drivers to analyze the labor burdens they endure. Based on the findings, the study suggests solutions such as improving working conditions, developing health support programs, and implementing more flexible policies to enhance the quality of life and job satisfaction among workers, thereby contributing to the sustainable development of the industry in Vietnam

Composted tobacco waste increases the yield and organoleptic quality of leaf mustard

Tobacco (Nicotiana tabacum) waste is produced in many countries and is phytotoxic due to the alkaloid content; in Vietnam the waste is usually burned causing air pollution. We composted tobacco waste with chicken manure in different proportions—1 t of waste ± accelerant (C1 and C2); 0.8 t of waste + 0.2 t of chicken manure ± accelerant (C3 and C4); and 0.7 t of waste + 0.3 t of chicken manure ± accelerant (C5 and C6)—for 30 d in covered heaps. Three mixtures containing the accelerant (C2, C4, and C6) reached temperatures of ∼55 °C, that 5s, hot enough to suppress disease and weeds. Composting decreased the alkaloid content from ∼6,000 to ∼200 mg kg−1, and C4 with a C/N ratio of 19:1, was used in a field trial. The compost treatments (0, 10, 15, and 20 t ha−1) were combined fertilizer with phosphorus (40 kg ha−1), nitrogen (60 kg ha−1) and potassium (90 kg ha−1) for leaf mustard (Brassica integrifolia). The yield increased from ∼17 to ∼29 t ha−1 with the amount of compost applied, and the nitrate concentration decreased concomitantly from ∼67 to ∼42 mg NO3–N kg−1 fresh weight, presumably due to ongoing composting (nitrogen drawdown). Organoleptic evaluation showed a preference for the crops grown with the compost amendments. Whether remains to be seen whether one-off compost applications >20 t ha−1 and repeated, large applications provide additional, long-term production benefits, or if the benefits may be outweighed by the accumulation of persistent, phytotoxic alkaloids

Data Structure Model on the Quality of Public Passenger Transport Services by Bus in Vietnam

The system of managing public passenger transport services (PPTS) by bus is a complex system, involving infrastructure, facilities, management and service communication activities between passengers and transport systems. In particular, quality information is the most important factor, providing necessary data for analysis, setting out measures to improve quality to meet the needs of passengers and meet the requirements of related parties. According to the peculiarity of the service, this study selects a database structure model to guide the process of computerizing the management of quality of PPTS by bus in urban areas in Vietnam. The results show that four database systems reflecting the quality information of the infrastructure, means of transport, transport operation and passenger service and each database system is structured by components that ensure proper implementation of QM process according to the continuous quality improvement cycle. The components of each database system are dispersed according to the scope of management to ensure the consistency for the quality management process and facilitate the collection, processing and distribution of information of related parties. Keywords: Quality, transport services, public passengers, Vietnam. DOI: 10.7176/JESD/10-10-13 Publication date:May 31st 201