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தொகுதி 7, பிரச்சினை 2 (2016)

ஆய்வுக் கட்டுரை

A Hybrid Optimization Technique Applied to the Intermediate-Target Optimal Control Problem

Clay J Humphreys, Richard G Cobb, David R Jacques, Jonah A Reeger

The DoD has introduced the concept of Manned-Unmanned Teaming, a subset of which is the loyal wingman. Optimal control techniques have been proposed as a method for rapidly solving the intermediate-target (mid-point constraint) optimal control problem. Initial results using direct orthogonal collocation and a gradient-based method for solving the resulting nonlinear program reveals a tendency to converge to or to get `stuck’ in locally optimal solutions. The literature suggested a hybrid technique in which a particle swarm optimization is used to quickly find a neighborhood of a more globally minimal solution, at which point the algorithm switches to a gradient-based nonlinear programming solver to converge on the globally optimal solution. The work herein applies the hybrid optimization technique to rapidly solve the loyal wingman optimal control problem. After establishing the background and describing the loyal wingman particle swarm optimization algorithm, the problem is solved first using the gradient-based direct orthogonal collocation method, then re-solved using a hybrid approach in which the results of the particle swarm optimization algorithm are used as the initial guess for the gradient-based direct orthogonal collocation method. Results comparing the final trajectory and convergence time, demonstrate the hybrid technique as a reliable method for producing rapid, autonomous, and feasible solutions to the loyal wingman optimal control problem.

ஆய்வுக் கட்டுரை

Energy Optimization of Steel in Electric Arc Furnace

Dora E Ledesma-Carrión

The aim of this work is to create a representative mathematical model of the process of steelmaking for the quantities of raw materials and energy consumption optimal for producing a ton of steel of the specific composition. The specific steel is grade 1010. The reaction enthalpies are critical in the conceptualization and the percentages of carbon and iron in the steelmaking process. There should be a maximum of FeO in slag and a bounded particle C. chemical reactions electric arc furnace enthalpies linear programming steel-making.

தலையங்கம்

Aligning the Most Advanced Technology With Green Engineering Principles – Can We Turn Back in Time?

Rui Galhano dos Santos

“Can we turn back the time?” Of course, we cannot, easy answer. What if the question was read or understood from another point of view, like, “Can we turn back to the world encountered when we became the Human species that we are? Can we start all over again? Can we make this a world a better place for us and next generations?” Actually, the question is almost the same; even if we cannot go back in time, at least turn the clock around, maybe we can recover part of that world, retaining all the commodities and comfort that we are used to.

தலையங்கம்

Inspiring Future Technology

Nader Barsoum

The new technology nowadays is based on smart systems, includes smart energy, smart grid, smart home, smart phone, smart plant irrigation system and smart technology. All are applicable to many medical, engineering, educational, shopping, banking, booking travel or hotels, commercial systems and devices. These are almost based on control and optimization programing algorithms and logic process which lead to time saving, energy saving, friendly use and cost effective. Most of these technologies are running online and wirelessly by the cellular phone in monitoring the measurements of the variables and to control the system or appliance by touching button and sending signals.

ஆய்வுக் கட்டுரை

Gamma Attenuation Coefficient of Carbonate Rocks Sampled from the North Western Coast of Egypt

Samir Al-Gamal, Sherine El-Essawy, El-Sayed M El-Refaie and Mohammed Durra

Gamma attenuation coefficients of host rocks belonging to Moghra Formation of Eocene era in one of two candidate sites located at the North Western Coast of Egypt in Al-Dabaa locality were estimated using Monte-Carlo Code for Nuclear Power (MCNP). Carbonates rock samples were taken to represents several depth intervals. A virtual mono-energetic gamma source with increasing energies was used. The gamma attenuation properties were found to be totally independent on the lithology of rock type, provided that roch sample density remains constant. Ultimately it is found that, gamma attenuation coefficient showed an inverse exponential dependence on the gamma energy regardless rock type and their related depth.
ஆய்வுக் கட்டுரை

A Journey to the Stars: Space Propulsion Brought About by Astrophysical Phenomena Such as Accretion Disk and Astrophysical Jet

Yoshinari Minami

At the present stage of space propulsion technology, the only practical propulsion system is chemical propulsion system and electric propulsion system, which are based on expulsion of a mass to induce a momentum thrust. Since the maximum speed is limited by the product of the gas effective exhaust velocity and the natural logarithm of mass ratio, its speed is too slow for the spaceship to achieve the interplanetary travel and interstellar travel. Thus the breakthrough of propulsion method has been required until now. Field propulsion systems, which are based on the General Relativity Theory, the Quantum Field Theory and other exotic theories, have been proposed to overcome the speed limit of the conventional space rocket, instead of conventional chemical propulsion systems.

ஆய்வுக் கட்டுரை

Improving the Functionality of Olive Oil by Cross Breeding

Yasin Ozdemir, Nesrin Aktepe Tangu and Hakan Yavas

This research is aimed to generate olive oils with increased functional properties and nutrient content. In this research, oils of 5 cultivar candidates were used as material. Maturation index of their fruits and alpha tocopherol and total phenol content and total antioxidant activities of their oils were evaluated. Results of this study showed that it is possible to develop and register new olive varieties which have olive oils with improved functional properties by cross breeding. LT001 and LT011 could be advised to enrich diet and for the preparation of functional food.

ஆய்வுக் கட்டுரை

Mitigating the Impact of NBTI and PBTI Degradation

Bairy B, Craig TS, Eshaghian-Wilner MM, Gonde K, Gupta N, Prajogi A and Saligram R

Modern CMOS devices encounter a major problem that alters the threshold voltages of the NMOS and PMOS. Negative Bias Temperature Instability (NBTI) and Positive Bias Temperature Instability (PBTI) are common ageing phenomena observed in PMOS and NMOS devices, respectively. Due to operating temperature and stress time, NBTI and PBTI create a decrease in drain-to-source current and an increase in propagation delay. Threshold voltage is an important parameter due to exponential dependence on delay and leakage power. Threshold voltage variations produce adverse effects on operation frequency. These phenomena accrue in pull-up/pull-down transistors in stack and vastly degrade CMOS performance. This paper discusses the various factors responsible for NBTI and PBTI and the challenges associated with modeling these effects due to the recovery mechanism exhibited by the transistors when the stress is removed. Therefore, we propose an algorithm to reduce the effects of NBTI and PBTI that will reduce the stress time for each transistor through the relative repositioning of the transistors based on the signal probability.

ஆய்வுக் கட்டுரை

True Angle between Anterior-Posterior Impingement in Total Hip Arthroplasty: Why Common Constrained Cups have to Fail

Andrej M. Nowakowski, Sebastian Gehmert, Irène Roesle and Karl-Heinz Widmer

Background: Dislocation after total hip arthroplasty is a common complication and partially based on impingement. Questions/purposes: (1) The purpose of this study was to investigate the angle between anterior and posterior impingement in current hip cup designs. (2) Furthermore, the aim was to design a model of an acetabular cup with sparing gaps that match to impact areas. Methods: The range of motion was simulated with Maple R8 software using standard parameters in hip arthroplasty. Afterwards, a preliminary model for an optimized acetabular cup was designed in order to avoid impingement and dislocation. Results: (1) Anterior and posterior areas of impingement were not opposite but twisted by an angle of 108.3°. (2) The two main trajectories of motion were identified and areas with corresponding reductions and elevations were appropriate modified. The improvement resulted in a “bidirectional total hip prosthesis” with a combination of a snapfit acetabular cup and a reduced cup profile. Conclusion: The improvements of the described hip prosthesis are based on a simulation and are most likely to prevent impingement and subsequent dislocation. In addition, simulation with standard implantation parameters resulted in a rotational asymmetric implant design. Clinical relevance: Our data provide evidence that conventional hip cup designs fail to prevent impingement due to (1) The incorrect assumption of diagonally arranged impingement areas and the diagonal arranged sparing gaps (2) The sparing gap design itself that technically is not reducing the rim of the cup but instead only has an elevated coverage relative to the center of motion.

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