Constraint checking during error recovery

The system-level software onboard a spacecraft is responsible for recovery from communication, power, thermal, and computer-health anomalies that may occur. The recovery must occur without disrupting any critical scientific or engineering activity that is executing at the time of the error. Thus, the error-recovery software may have to execute concurrently with the ongoing acquisition of scientific data or with spacecraft maneuvers. This work provides a technique by which the rules that constrain the concurrent execution of these processes can be modeled in a graph. An algorithm is described that uses this model to validate that the constraints hold for all concurrent executions of the error-recovery software with the software that controls the science and engineering activities of the spacecraft. The results are applicable to a variety of control systems with critical constraints on the timing and ordering of the events they control

Experimental study on concrete of blended cement with eggshell powder and fly ash

Cement as a vital material of concrete production plays an important role in construction field. However, production of cement had brought severe negative impact to environment. Research found that there is approximately 780 kg of carbon dioxide (CO2) is emitted to atmosphere for every ton of cement produced. In order to minimize the negative effect of cement production, alternative environmental friendly material should be determined. In the past decade, consumer waste and industrial by-product handling method always become an environmental issue. Disposal of egg shells through landfilling might detrimental to human health as it may become the habitat for vermin. Fly ash as industrial by product had led to severe disposal and leachate problem also. Recent researches have proposed that these waste materials can be recycled and added to concrete as an effort to minimize post-consumer wastes and industrial by-products entering the landfills. Egg shells riches in pure form of calcium carbonate (CaCO3) which is nearly similar as composition of limestone. The composition of fly ash includes substantial amounts of silicon dioxide (SiO2), aluminium oxide (Al2O3) and calcium oxide (CaO). When they mix with Portland cement and water, it will result in production of calcium-silicates hydrates (C-S-H) which primarily responsible for the strength of concrete. As there is potential of developing these waste product as construction material, investigation is conducted to determine the mechanical properties and optimum mix design of blended cement with egg shells powder and fly ash. In this investigation, a combination of 30% of fly ash and four different percentages of eggshell powder with respect to cement were added into the concrete mix of Grade M30. The materials used in this experimental study involved non-composite Portland cement, coarse aggregate, fine aggregate, sand, Class C fly ash and eggshell powder. From the investigation, all the casted concrete has achieved the designated compressive strength of 30MPa. 30% of fly ash and 5% of eggshell powder is the optimum dosage for concrete to achieve higher flexural strength. Besides, the splitting tensile strength of concrete decrease with the further increase in proportion of fly ash and eggshell powder

The inherent danger in laser safety eyewear

I have designed an experiment which explained why the filter in a laser protective eyewear could crack under prolonged contact to a laser beam. My hypothesis stated that the nonlinearity of absorption of light played an important role in the failure of the filter. Using a xeon-arc lamp, a photoconductive cell, a multimeter and filters that consisted of 0 to 15 blue transparency(ies), I indirectly measured the amount of light that these filter absorbed. From the data I affirmed my hypothesis. If a laser beam hit an actual protective filter, because of the nonlinearity of absorption, the front surfaces of the filters would absorb much more laser light than the back surfaces. thus the front would heat up and expand more quickly than the back causing the filter to crack. Because future optometrists will need to learn the practical significance of the nonlinear process of absorption, I have also incorporated my experimental procedure into a physical optics experiment

Tree-based Algorithm to Find the k-th Value in Distributed Systems

In this paper, we study distributed algorithms for finding the k-th value in the decentralized systems. First we consider the case of circular configuration of processors where no processor knows the total number of participants. Later a network of arbitrary configuration is examined and a tree-based algorithm is proposed. The proposed algorithm requires O(N) messages and O(log N) rounds of message passing, where N is the number of nodes in the network

MATURE-HEALTH: HEALTH Recommender System for MAndatory FeaTURE choices

Balancing electrolytes is utmost important and essential for appropriate functioning of organs in human body as electrolytes imbalance can be an indication of the development of underlying pathophysiology. Efficient monitoring of electrolytes imbalance not only can increase the chances of early detection of disease, but also prevents the further deterioration of the health by strictly following nutrient controlled diet for balancing the electrolytes post disease detection. In this research, a recommender system MATURE Health is proposed and implemented, which predicts the imbalance of mandatory electrolytes and other substances presented in blood and recommends the food items with the balanced nutrients to avoid occurrence of the electrolytes imbalance. The proposed model takes user most recent laboratory results and daily food intake into account to predict the electrolytes imbalance. MATURE Health relies on MATURE Food algorithm to recommend food items as latter recommends only those food items that satisfy all mandatory nutrient requirements while also considering user past food preferences. To validate the proposed method, particularly sodium, potassium, and BUN levels have been predicted with prediction algorithm, Random Forest, for dialysis patients using their laboratory reports history and daily food intake. And, the proposed model demonstrates 99.53 percent, 96.94 percent and 95.35 percent accuracy for Sodium, Potassium, and BUN respectively. MATURE Health is a novel health recommender system that implements machine learning models to predict the imbalance of mandatory electrolytes and other substances in the blood and recommends the food items which contain the required amount of the nutrients that prevent or at least reduce the risk of the electrolytes imbalance.Comment: Author version of the pape

Determination of hawser forces using numerical and physical models for the third set of Panama locks studies

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General Lidstone Problems: Multiplicity and Symmetry of Solutions

AbstractFor the 2mth order Lidstone boundary value problem,y(2m)t=fyt,y″t,…,y(2i)t,…,y(2(m−1))t,t∈0,1, y(2i)0=y(2i)1=0,0≤i≤m−1, where (−1)mf: Rm→[0,$thinsp;∞) is continuous, growth conditions are imposed on f which yield the existence of at least three symmetric positive solutions. This generalizes earlier papers which have applied Avery's generalization of the Leggett–Williams theorem to Lidstone problems. We then prove the analogous result for difference equations