Joint Data compression and Computation offloading in Hierarchical Fog-Cloud Systems

Data compression has the potential to significantly improve the computation offloading performance in hierarchical fog-cloud systems. However, it remains unknown how to optimally determine the compression ratio jointly with the computation offloading decisions and the resource allocation. This joint optimization problem is studied in the current paper where we aim to minimize the maximum weighted energy and service delay cost (WEDC) of all users. First, we consider a scenario where data compression is performed only at the mobile users. We prove that the optimal offloading decisions have a threshold structure. Moreover, a novel three-step approach employing convexification techniques is developed to optimize the compression ratios and the resource allocation. Then, we address the more general design where data compression is performed at both the mobile users and the fog server. We propose three efficient algorithms to overcome the strong coupling between the offloading decisions and resource allocation. We show that the proposed optimal algorithm for data compression at only the mobile users can reduce the WEDC by a few hundred percent compared to computation offloading strategies that do not leverage data compression or use sub-optimal optimization approaches. Besides, the proposed algorithms for additional data compression at the fog server can further reduce the WEDC

An inquiry into the determinants of Vietnamese product export

Export led growth is the model of economic development that Vietnam has been following. While there are a great number of studies on the determinants of aggregate export of Vietnam, there are few that analyze the impacts of different factors on the export of different product groups. This paper aims at filling this gap in research on international trade of Vietnam. The results show that the fast GDP growth of Vietnam, the large population of importing countries, the wide economic gap between Vietnam and the importing countries, the depreciation of domestic currency, the free trade agreements that Vietnam signed and the shared border with the importing countries contribute to the increase of Vietnam’s export of all product groups. In contrast, the GDP of importing countries and population of Vietnam have no clear impacts on the export of any product groups.

Integral manifolds for semilinear evolution equations and admissibility of function spaces

We prove the existence of integral (stable, unstable, and center) manifolds for the solutions to a semilinear integral equation in the case where the evolution family (U(t, s)) t≥s has an exponential trichotomy on a half line or on the whole line, and the nonlinear forcing term f satisfies the φ-Lipschitz conditions, i.e., where φ(t) belongs to some classes of admissible function spaces. Our main method is based on the Lyapunov–Perron methods, rescaling procedures, and the techniques of using the admissibility of function spaces.Доведено iснування iнтегральних (стiйких, нестiйких, центральних) многовидiв для розв’язкiв напiвлiнiйного iнтегрального рiвняння у випадку, коли сiм’я еволюцiй (U(t,s))tleqs має експоненцiальну трихотомiю на пiвосi або на всiй осi, а нелiнiйний збурюючий член f задовольняє φ-лiпшицевi умови, тобто належить до деяких класiв допустимих просторiв функцiй. Наш основний метод базується на методах Ляпунова – Перрона, процедурах перемасштабування та технiцi застосування допустимостi просторiв функцiй

Acquisition/apprentissage des relatives en français par des étudiants vietnamiens en FLE

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

On the Interference Alignment Designs for Secure Multiuser MIMO Systems

In this paper, we propose two secure multiuser multiple-input multiple-output transmission approaches based on interference alignment (IA) in the presence of an eavesdropper. To deal with the information leakage to the eavesdropper as well as the interference signals from undesired transmitters (Txs) at desired receivers (Rxs), our approaches aim to design the transmit precoding and receive subspace matrices to minimize both the total inter-main-link interference and the wiretapped signals (WSs). The first proposed IA scheme focuses on aligning the WSs into proper subspaces while the second one imposes a new structure on the precoding matrices to force the WSs to zero. When the channel state information is perfectly known at all Txs, in each proposed IA scheme, the precoding matrices at Txs and the receive subspaces at Rxs or the eavesdropper are alternatively selected to minimize the cost function of an convex optimization problem for every iteration. We provide the feasible conditions and the proofs of convergence for both IA approaches. The simulation results indicate that our two IA approaches outperform the conventional IA algorithm in terms of average secrecy sum rate.Comment: Updated version, updated author list, accepted to be appear in IEICE Transaction

MATERIAL FLOW ANALYSIS (MFA) AND ENERGY BALANCE ANALYSIS (EBA) AS TECHNICAL TOOLS FOR WASTEWATER POLLUTION CONTROL IN TEXTILE AND DYEING INDUSTRY – A CASE STUDY

The textile and dyeing industry consumes a large amount of water and discharges to the environment many pollutants including dyestuffs, auxiliaries, others. In this study, a selected textile and dyeing company was representing modern factory in Vietnam. Using STAN software, the authors have quantified and analyzed the material flows of the production lines and of the main pollutants in wastewater. Comparing with “business as usual” scenario, a new scenario with treatment and reuse of wastewater has been introduced. The discharge volume of wastewater from company was about 3,608.96 m3/day (or 1,317,270.4 m3/year). Loadings of the main pollutants in wastewater as COD, TSS, T-P and T-N were 1419.95, 1571.36, 17.77 and 50.16 ton/year, respectively. One meter of produced fabric consumes 0.025 m3 of water. Energy consumption of the wastewater treatment station was analyzed by SANKEY software. The energy consumption rate was 1.695 kWh per m3 of wastewater. Reuse of wastewater could save 1,129.05 kWh per day of electricity and 1,804.48 m3 per day of fresh water to be taken from the river source. Ozonation was the most consuming energy process at the wastewater treatment station, accounting for 58.88% of total wastewater treatment energy consumption

Computation Offloading and Resource Allocation for Backhaul Limited Cooperative MEC Systems

In this paper, we jointly optimize computation offloading and resource allocation to minimize the weighted sum of energy consumption of all mobile users in a backhaul limited cooperative MEC system with multiple fog servers. Considering the partial offloading strategy and TDMA transmission at each base station, the underlying optimization problem with constraints on maximum task latency and limited computation resource at mobile users and fog servers is non-convex. We propose to convexify the problem exploiting the relationship among some optimization variables from which an optimal algorithm is proposed to solve the resulting problem. We then present numerical results to demonstrate the significant gains of our proposed design compared to conventional designs without exploiting cooperation among fog servers and a greedy algorithm

Total soluble and insoluble oxalate contents of ripe green and golden kiwifruit

Three bulk samples of two different cultivars of kiwifruit, green (Actinidia deliciosa L.) and golden (Actinidia chinensis L.) were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW) and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW) when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW), while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW

Current Status of Elderly Social Support Services in Elderly Care Centers in Hanoi

The Article aims to elaborate and analyze the current status of social support services for the elderly in general and semi-professional social work services provided in care centers in Hanoi in particular today. The centers subject to the investigation include Social Protection Center 3 Hanoi, Dien Hong Nursing Home, Bach Nien Thien Duc Elderly Care Center, and Social Protection Center 2 Hanoi. The service performance is determined based on the satisfaction of the needs of the elderly group. The results evidence that from the point of view of the elderly, “the need for medical care, examination and treatment is the highest among other needs of the elderly (with 149 votes, taking up 64.2%), from the point of view of social support workers, the need for “someone to share their feelings” is the highest (with 144 votes, taking up 77.4%). The services subject to assessment and review to the extent of the Article include (1) Consultancy; (2) Legal aid; (3) Supporting the elderly in the integration; (4) Communication. The frequency of rendered services changes at the “sometimes received by the elderly” level, approx. 50% on average. The level of performance as assessed by the elderly and social workers is at a medium and quite high level, ranging from 2.26 to 3.30 and from 1.98 (high) to 3.1 (medium), respectively.  Keywords: the elderly, social support services, care centers DOI: 10.7176/RHSS/12-20-04 Publication date:October 31st 202