Detecting Signals with Unknown Duration and/or Starting Time: Sequential Detectors

2019 ◽  
pp. 743-818
Author(s):  
Douglas A. Abraham
Keyword(s):  
Starting Time

scholarly journals Estimation of the Starting Time of Stem Elongation Based on Internode Length Pattern and Number of Expanded Leaves in Sweet Sorghum

2015 ◽  
Vol 84 (2) ◽  
pp. 209-212
Author(s):  
Akihiro Fujii ◽  
Satoshi Nakamura ◽  
Keita Nabeya ◽  
Yusuke Goto
Keyword(s):  
Sweet Sorghum ◽  
Stem Elongation ◽  
Internode Length ◽  
Starting Time

Starting time for induction of labor and the risk for night-time delivery

2011 ◽  
Vol 2 (3) ◽  
pp. 113-117 ◽  
Author(s):  
M. Thorsell ◽  
S. Lyrenäs ◽  
E. Andolf ◽  
M. Kaijser
Keyword(s):  
Induction Of Labor ◽  
Night Time ◽  
Starting Time

Slack Due-Window Assignment Scheduling Problem with Deterioration Effects and a Deteriorating Maintenance Activity

2022 ◽  
Author(s):  
Xue Jia ◽  
Dan-Yang Lv ◽  
Yang Hu ◽  
Ji-Bo Wang ◽  
Zhi Wang ◽  
...  
Keyword(s):  
Polynomial Time Algorithm ◽  
Time Algorithm ◽  
Machining Process ◽  
Scheduling Problem ◽  
Maintenance Activity ◽  
Starting Time ◽  
Weighted Number ◽  
Deteriorating Maintenance ◽  
Due Window ◽  
Due Window Assignment

This paper studies the slack due-window assignment scheduling problem with deterioration effects and a deterioration maintenance activity on a single-machine. The machine deteriorates during the machining process, and at a certain moment performs a deterioration maintenance activity, that is, the duration time of the maintenance activity is a linear function of the maintenance starting time. It is needed to make a decision on when to schedule the deteriorating maintenance activity, the optimal common flow allowances and the sequence of jobs to minimize the weighted penalties for the sum of earliness and tardiness, weighted number of early and delayed, and weighted due-window starting time and size. This paper proposes a polynomial time algorithm to solve this problem.

scholarly journals Sleep habits and starting time to school in Brazilian children

2005 ◽  
Vol 63 (2b) ◽  
pp. 402-406 ◽  
Author(s):  
Tatiana A. Silva ◽  
Luciane B.C. Carvalho ◽  
Luciana Silva ◽  
Marilaine Medeiros ◽  
Vivian B. Natale ◽  
...  
Keyword(s):  
Total Sleep Time ◽  
Sleep Time ◽  
Sao Paulo ◽  
São Paulo ◽  
Sleep Habits ◽  
Progressive Reduction ◽  
Starting Time ◽  
Brazilian Children

OBJECTIVE: This study investigated the sleep habits in Brazilian children according to age, gender and starting time to school. METHOD: We investigated 2,482 scholars aged 7 to 10 years. We compared sleep habits, gender, and starting time to school (morning and afternoon). RESULTS: Sixty-one per cent of the children presented sleep rituals before sleep. Milk drinking before sleep was more frequent among seven years old children. We found a progressive reduction with age in keeping the lights on. Girls used to leave an object to bed more than boys did. Children that studied in the morning presented reduced total sleep time, sleep earlier, and nap more frequently than children that studied in the afternoon. CONCLUSION: Starting time to school deeply influences sleep habits in Brazilian children from São Paulo City, in whom bed-time rituals are highly prevalent.

Revisiting Current Techniques for Analyzing Reservoir Performance: A New Approach for Horizontal-Well Pseudosteady-State Productivity Index

SPE Journal ◽  
2018 ◽  
Vol 24 (01) ◽  
pp. 71-91 ◽  
Author(s):  
Salam Al-Rbeawi
Keyword(s):  
Porous Media ◽  
Pressure Drop ◽  
Transient State ◽  
Darcy Flow ◽  
Analytical Models ◽  
Productivity Index ◽  
Pressure Derivative ◽  
Starting Time ◽  
State Flow ◽  
State Pressure

Summary The objective of this paper is to revisit currently used techniques for analyzing reservoir performance and characterizing the horizontal-well productivity index (PI) in finite-acting oil and gas reservoirs. This paper introduces a new practical and integrated approach for determining the starting time of pseudosteady-state flow and constant-behavior PI. The new approach focuses on the fact that the derivative of PI vanishes to zero when pseudosteady-state flow is developed. At this point, the derivative of transient-state pressure drop and that of pseudosteady-state pressure drop become mathematically identical. This point indicates the starting time of pseudosteady-state flow as well as the constant value of pseudosteady-state PI. The reservoirs of interest in this study are homogeneous and heterogamous, single and dual porous media, undergoing Darcy and non-Darcy flow in the drainage area, and finite-acting, depleted by horizontal wells. The flow in these reservoirs is either single-phase oil flow or single-phase gas flow. Several analytical models are used in this study for describing pressure and pressure-derivative behavior considering different reservoir configurations and wellbore types. These models are developed for heterogeneous and homogeneous formations consisting of single and dual porous media (naturally fractured reservoirs) and experiencing Darcy and non-Darcy flow. Two pressure terms are assembled in these models; the first pressure term represents the time-dependent pressure drop caused by transient-state flow, and the second pressure term represents time-invariant pressure drop controlled by the reservoir boundary. Transient-state PI and pseudosteady-state PI are calculated using the difference between these two pressures assuming constant wellbore flow rate. The analytical models for the pressure derivatives of these two pressure terms are generated. Using the concept that the derivative of constant PI converges to zero, these two pressure derivatives become mathematically equal at a certain production time. This point indicates the starting time of pseudosteady-state flow and the constant behavior of PI. The outcomes of this study are summarized as the following: Understanding pressure, pressure derivative, and PI behavior of bounded reservoirs drained by horizontal wells during transient- and pseudosteady-state production Investigating the effects of different reservoir configurations, wellbore lengths, reservoir homogeneity or heterogeneity, reservoirs as single or dual porous media, and flow pattern in porous media whether it has undergone Darcy or non-Darcy flow Applying the concept of the PI derivative to determine the starting time of pseudosteady-state stabilized PI The novel points in this study are the following: The derivative of the PI can be used to precisely indicate the starting time of pseudosteady-state flow and the constant behavior of PI. The starting time of pseudosteady-state flow determined by the convergence of transient- and pseudosteady-state pressure derivative or by the PI curve is always less than that determined from the curves of total pressure drop and its derivative. Non-Darcy flow may significantly affect the transient-state PI, but pseudosteady-state PI is slightly affected by non-Darcy flow. The starting time of pseudosteady-state flow is not influenced by non-Darcy flow. The convergence of transient- and pseudosteady-state pressure derivatives is affected by reservoir configurations, wellbore lengths, and porous-media characteristics.

Applying Hollow Blades for Small Wind Turbines Operating at High Altitudes

2015 ◽  
Author(s):  
Abolfazl Pourrajabian ◽  
Reza Ebrahimi ◽  
Masoud Mirzaei ◽  
Mehdi Ahmadizadeh ◽  
David Wood
Keyword(s):  
Objective Function ◽  
Output Power ◽  
Wind Turbines ◽  
Speed Ratio ◽  
High Altitudes ◽  
Horizontal Axis Wind Turbine ◽  
Lower Altitude ◽  
Starting Time ◽  
Design Variables ◽  
Small Wind Turbines

Since the air density reduces as the altitude increases, operation of Small Wind Turbines (SWTs) which usually have no pitch mechanism, remains as a challengeable task at high altitudes due largely to the reduction of starting aerodynamic torque. By reducing the blades moment of inertia through the use of hollow blades, the study aims to mitigate that issue and speed up the starting. A three-bladed, 2 m diameter small horizontal axis wind turbine with hollow cross-section was designed for operating at two sites with altitude of 500 and 3,000 m. The design variables consist of distribution of the chord, twist and shell thickness along the blade. The blade-element momentum theory was employed to calculate the output power and starting time and, the beam theory was used for the structural analysis to investigate whether the hollow blades could withstand the aerodynamic and centrifugal forces. A combination of the starting time and the output power was included in an objective function and then, the genetic algorithm was used to find a blade for which the output power and the starting performance, the goals of the objective function, are high while the stress limitation, the objective function constraint, is also met. While the resultant stresses remain below the allowable stress, results show that the performance of the hollow blades is far better than the solid ones such that their starting time is shorter than the solid blades by approximately 70%. However, in the presence of the generator resistive torque, the algorithm could not find the blade for the altitude near to 3000 m. To solve that problem, the tip speed ratio of the turbine was added to other design variables and another optimization process was done which led to the optimal blades not only for the lower altitude but also for the higher one.

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