366 research outputs found
A realization model to develop the autopilot system of ships by specializing MDA
This paper presents a method which is based on the Model-Driven Architecture (MDA) and functional blocks to realize effectively the autopilot systems of ships. It brings out an executable MDA process to cover completely the requirement analysis, design and deployment phases of these systems. This process also allows the determined design elements to be customizable and re-usable in the new applications of controlled ship steering systems. The paper indicates straightforwardly the ship dynamic model-to-be used, the Computation Independent Model (CIM) of a ship autopilot system, the Platform Independent Model (PIM) of this system by using the Real-Time Unified Modeling Language (UML), and its Platform Specific Model (PSM) implemented by the functional blocks. Furthermore, the important transformation rules are also brought out and applied to convert the identified PIM into PSM for implementing quickly this system with different industrial frameworks such as the IEC61499 in a programmable controller. Then, its deployment model completely is tested on a model ship with the predetermined program and control performance
Joint Resource Optimization for Multicell Networks with Wireless Energy Harvesting Relays
This paper first considers a multicell network deployment where the base
station (BS) of each cell communicates with its cell-edge user with the
assistance of an amplify-and-forward (AF) relay node. Equipped with a power
splitter and a wireless energy harvester, the self-sustaining relay scavenges
radio frequency (RF) energy from the received signals to process and forward
the information. Our aim is to develop a resource allocation scheme that
jointly optimizes (i) BS transmit powers, (ii) received power splitting factors
for energy harvesting and information processing at the relays, and (iii) relay
transmit powers. In the face of strong intercell interference and limited radio
resources, we formulate three highly-nonconvex problems with the objectives of
sum-rate maximization, max-min throughput fairness and sum-power minimization.
To solve such challenging problems, we propose to apply the successive convex
approximation (SCA) approach and devise iterative algorithms based on geometric
programming and difference-of-convex-functions programming. The proposed
algorithms transform the nonconvex problems into a sequence of convex problems,
each of which is solved very efficiently by the interior-point method. We prove
that our algorithms converge to the locally optimal solutions that satisfy the
Karush-Kuhn-Tucker conditions of the original nonconvex problems. We then
extend our results to the case of decode-and-forward (DF) relaying with
variable timeslot durations. We show that our resource allocation solutions in
this case offer better throughput than that of the AF counterpart with equal
timeslot durations, albeit at a higher computational complexity. Numerical
results confirm that the proposed joint optimization solutions substantially
improve the network performance, compared with cases where the radio resource
parameters are individually optimized
EU-VIETNAM FREE TRADE AGREEMENT (EVFTA) AND VIETNAM AGRICULTURAL PRODUCTS EXPORT: OPPORTUNITIES AND CHALLENGES
EVFTA is a newly generated free trade agreement with the highest level of commitment that a partner has for Vietnam among the FTAs ​​ signed. Regarding agricultural products, which are Vietnam's strengths, the EVFTA's commitments bring opportunities to expand and diversify export markets; increase exports and promote the improvement of agricultural product quality. In order to meet the strict requirements of the EU, stakeholders including the Government, production facilities, and exporters of Vietnamese agricultural products must take advantage of opportunities and overcome challenges as a result of the EVFTA. By analyzing opportunities and challenges, the article proposes some solutions to take advantage of opportunities and remove difficulties in exporting Vietnamese agricultural products to the EU
Secure Information Flow for IoT Applications
This paper discusses how to ensure security, i.e., confidentiality and integrity properties, for data in IoT applications. While confidentiality could be assessed via information flow analysis, integrity is ensured by error-correcting codes. In addition to errors, many communication channels also cause erasures, i.e., the demodulator cannot decide which symbol the received waveform represents. The paper proposes a method that might correct both errors and erasures together. Our method is efficient in reducing memory storage as well as decoding complexity
COMPARISON OF ETHANOL YIELD BETWEEN SEPARATE AND SIMULTANEOUS HYDROLYSIS AND ETHANOL FERMENTATION OF FORMIC- FRACTIONATED SUGARCANE BAGASSE
The fractionation of sugarcane bagasse using formic acid allowed removing lignin and hemicellulose, obtaining a material containing up to 90 % cellulose. The material can be easily hydrolyzed into glucose to serve as materials to produce high value added products such as biofuel, chemicals, pharmaceuticals, food additives, and the likes. The hydrolysate of fractionated bagasse was easily fermented with a (ethanol) fermentation yield attained 91.08 ± 2.02 %, showing no significant inhibition to the yeast in the hydrolysate. In this study, a process of simultaneous hydrolysis and fermentation (SSF) was performed to convert fractionated sugarcane bagasse at 20 % consistency to ethanol. The process with 6h pre-hydrolysis at 50 0C then SSF at 37 0C could attain a high ethanol concentration of 82.46 ± 3.42 g/L in the fermentation with the ethanol recovery yield of 81.66±1.88%; which was15.37 ± 1.06 % higher than that of the separate hydrolysis and fermentation (SHF) process (70.78 ± 0.25 %). In addition, in the SSF, the process time was shorten to 4 days instead of 7 days in the SHF
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