Finding all the Lower Boundary Points in a Multistate Two-Terminal Network

2017 ◽  
Vol 66 (3) ◽  
pp. 677-688 ◽  
Author(s):  
Majid Forghani-elahabad ◽  
Luiz Henrique Bonani
Keyword(s):  
Lower Boundary ◽  
Boundary Points

scholarly journals PROCESSING OF HARDENED CYLINDRICAL GEAR WHEELS OF THE CUTTING GEARBOX OF THE COMBINE UKD 200-500

2021 ◽  
pp. 57-70
Author(s):  
Oleksandr Koval'chuk ◽  
Volodymyr Nezhebovs'kyj ◽  
Alexander Permyakov ◽  
Alexander Klochko ◽  
Serhii Riabchenko
Keyword(s):  
Coal Mining ◽  
Lower Boundary ◽  
Cylindrical Gear ◽  
Gear Teeth ◽  
Cylindrical Gears ◽  
Boundary Points ◽  
Gear Grinding ◽  
Gear Wheels ◽  
Technological Methods

The article discusses the latest developments of unique technological methods of gear milling of cylindrical gears for preliminary blade gear processing of hardened cylindrical gears of the cutting reducer of the UKD200-500 coal mining harvester for the final gear grinding of gear teeth with modulus m = 16 mm, with hardness HRC 56 ... 62. The peculiarity of the design of special hob cutters is that a circle passing through the lower boundary points of the involute is used as the palloid of the machine gearing of the tool and part. Pre-cutting the teeth of hardened wheels with carbide milling cutters allows you to remove the main allowance for the final gear grinding.

scholarly journals Reliability Evaluation for a Stochastic Flow Network Based on Upper and Lower Boundary Vectors

Mathematics ◽  
2019 ◽  
Vol 7 (11) ◽  
pp. 1115
Author(s):  
Huang ◽  
Huang ◽  
Lin
Keyword(s):  
Lower Boundary ◽  
Reliability Evaluation ◽  
Exclusion Principle ◽  
Stochastic Flow ◽  
Decomposition Approach ◽  
Flow Network ◽  
Boundary Points ◽  
Classic Problem ◽  
Upper Boundary

For stochastic flow network (SFN), given all the lower (or upper) boundary points, the classic problem is to calculate the probability that the capacity vectors are greater than or equal to the lower boundary points (less than or equal to the upper boundary points). However, in some practical cases, SFN reliability would be evaluated between the lower and upper boundary points at the same time. The evaluation of SFN reliability with upper and lower boundary points at the same time is the focus of this paper. Because of intricate relationships among upper and lower boundary points, a decomposition approach is developed to obtain several simplified subsets. SFN reliability is calculated according to these subsets by means of the inclusion-exclusion principle. Two heuristic options are then established in order to calculate SFN reliability in an efficient direction based on the lower and upper boundary points.

scholarly journals Genetic Algorithm for solving flow problems in a Stochastic-flow Network under Budget Constraints

2014 ◽  
Vol 12 (8) ◽  
pp. 3749-3757
Author(s):  
M. R. Hassan
Keyword(s):  
Genetic Algorithm ◽  
Lower Boundary ◽  
Flow Network ◽  
Total Transmission ◽  
Flow Problems ◽  
Boundary Points ◽  
Transmission Cost ◽  
Flow Vector ◽  
Feasible Solutions ◽  
The Given

The system reliability (Rd,c) calculation is based on the generation of all the lower boundary points for the given demand, d, such that the total transmission cost is less than or equal to c (budget). This generation of the lower boundary points is based on finding all feasible solutions to the flow vector, F. The number of feasible solutions cannot be anticipated. Thus, a genetic algorithm is useful for solving this problem. Therefore, this paper presents a genetic algorithm to generate all feasible solutions to the flow vector, F, and then calculate Rd,c. The algorithm is applied to two problem models. In the first, each arc of a flow network has several capacities and may fail. In the second, both the arc and node have several capacities and may fail. The results show that the algorithm is efficient at solving a flow problem and is useful for calculating Rd,c.

Research on composite bending stress of asymmetric gear in consideration of friction

2018 ◽  
Vol 233 (8) ◽  
pp. 2939-2955 ◽  
Author(s):  
Shuai Mo ◽  
Shuai Ma ◽  
Guoguang Jin
Keyword(s):  
Shear Stress ◽  
Friction Force ◽  
Lower Boundary ◽  
Element Model ◽  
Spur Gears ◽  
Bending Stress ◽  
Object A ◽  
Boundary Points ◽  
Single Tooth ◽  
Meshing Process

Compared with the conventional gear, the asymmetric gear has better root bending stress and tooth contact stress. Taking a pair of asymmetric involute spur gears as the research object, a model of asymmetric gear considering the influence of friction and shear stress on root bending stress is established. Take the upper boundary point of single tooth meshing area as example, the formula for calculating root bending stress of asymmetric gear is deduced under friction, get the rule of root bending stress without neglecting the friction force and the shear stress by MATLAB. At the same time, we design the plane finite element model of conventional gear (20°/20°) and asymmetric gear (20°/35°) by using APDL. The upper and lower boundary points of the double tooth meshing area, the upper and lower boundary points of the single tooth meshing area, the meshing node are systematically studied, get the change rules of root bending stress in the meshing process under the condition that the friction force cannot be ignored.

Morphometric characteristics of competent proximal valves of the great saphenous vein and superficial femoral vein in vivo according to ultrasound angioscanning data

2019 ◽  
Vol 18 (3) ◽  
pp. 16-22
Author(s):  
E. K. Gavrilov ◽  
H. L. Bolotokov ◽  
E. A. Babinets
Keyword(s):  
Saphenous Vein ◽  
Great Saphenous Vein ◽  
Femoral Vein ◽  
Lower Boundary ◽  
Average Diameter ◽  
Lower Limbs ◽  
Functional Test ◽  
Natural Form ◽  
Superficial Femoral Vein ◽  
Venous Diameter

Introduction. It seems relevant to study the ultrasound anatomy and physiology of the proximal valve segments of the superficial femoral vein (SFV) and the great saphenous vein (GSV) to develop effective reconstructive surgical interventions on venous valves in chronic vein diseases.The aim of the survey was to study the ultrasound anatomy of the venous wall, the size and shape of the proximal SFV and GSV valves are normal at rest and during the functional test Valsalva.Material and methods. Proximal valve SFV studies were performed in 144 lower limbs in 115 people (mean age 51.1 ± 14.4 years, 60 women and 55 men), proximal GSV valves studies - in 82 lower limbs in 67 persons (average age 45, 1 ± 13.3 years, 33 women, 34 men). A longitudinal and transverse ultrasound scanning of the femoral vein bifurcation and safenofemoral junction areas were performed, the structures of the proximal SFV and GSV valves were visualized, the valve shape was measured and the diameter of the veins was measured at the level valves at the base of the valves (inlet diameter), at the point of maximum ectasia (diameter of ectasia), at the upper border of the valve (diameter of the outlet), as well as measuring the length of the valve a (length to ectasia, the total length of the valve). The degree of ectasia over the valve was judged by calculating the relative venous diameter change (RVDC).Results. the average diameter of the SFV at the level of the lower boundary of its first valve was 10.01 ± 1.44 mm. The average diameter of the SFV at the level of the maximum ectasia of its first valve was 13,1±2 mm. The average value of the index of RVDC for SFV was 31%±10,4%. An increase in the diameter of the vein in the zone of supravalvular ectasia up to 20% corresponded to the spindle-shaped valve, more than 20% - to the clavate form, which was noted in the majority of the examined. The change in the relative venous diameter of the SFV on the Valsalva test was 38,2%±12,4%. The average diameter of the GSV at the base of the first valves was 6,07±1,25 mm. The average diameter of the GSV at the level of the maximum ectasia of the osteal valve was 9,44±1,69 mm. The average RVDC for GSV was 58%±24%.Conclusion. the natural form of proximal SFV and GSV valves is clavate with presence of the significant supravalvular ectasia, which was noted in the majority of the subjects alone and in all during the performance of the Valsalva functional test.

Assessment of nutritional status of students of medical institute according to the blood biochemical parameters

2020 ◽  
pp. 55-63
Author(s):  
Rofail Rakhmanov ◽  
Elena Bogomolova ◽  
Mariya Shaposhnikova ◽  
Mariya Sapozhnikova
Keyword(s):  
Nutritional Status ◽  
Lower Boundary ◽  
Density Lipoprotein ◽  
Blood Parameters ◽  
Medical Institute ◽  
Specific Situation ◽  
Mathematical Methods ◽  
Normal Range ◽  
Mean Values ◽  
The Mean

The biochemical blood parameters characterizing the students ’nutritional status were evaluated: protein, lipid, carbohydrate metabolism, a number of minerals. The mean values, errors of the mean, median (Me), boundary (Q) and the range of 25–75 percentiles were determined. In 9.1 % of students and 28.6 % of students, the total protein was increased. Creatinine in men was in the upper normal range, in women — at the upper limit of normal, of which 46.2 % was higher than normal. The interval Q25–75 of uric acid in students is determined in the lower normal zone. In 40.0 % of men, decreased high-density lipoprotein cholesterol (Q25–75 corresponded to 1.15–1.79), in women — below normal, Q25–75 5 was 1.3–1.5, decreased in 73.3 %. Me and Q25–75 iron were in the lower normal range; 14.1 % of men and 13.2 % of women are below normal. Me sodium and potassium at the level of the lower boundary of the norm, Q25–75 in the lower zone of the norm: in 16.0 % and 15.4 % of students the levels are reduced. Calcium is slightly above the lower limit of the norm, Q25–75–2.1–2.24, indicating an insufficient intake in the whole group; 25.0 % are below normal. The border of the 25th percentile of magnesium is at the level of the lower border of the norm, in 19.2 % it is reduced. 7.2 % lack of chlorine. Phosphorus is normal, but Q25–75 is in the upper zone; 17.9 % increased. Biochemical markers can identify individuals with metabolic disorders of nutrients. Statistical indicators — the median, the boundaries of 25–75 quartiles and their scope characterize the metabolism of macronutrients and minerals in the group and subgroups of students. Laboratory and mathematical methods can provide a basis for identifying the specific causes of these changes. For this, you can use the questionnaire method of studying the nutrition of students, possibly using the developed questionnaires for a specific situation.

scholarly journals Frictional properties of anorthite (feldspar): implications for the lower boundary of the seismogenic zone

2020 ◽  
Vol 72 (1) ◽  
Author(s):  
Koji Masuda
Keyword(s):  
Dominant Role ◽  
Lower Boundary ◽  
Earthquake Magnitude ◽  
Seismogenic Zone ◽  
Effective Pressure ◽  
Velocity Dependence ◽  
Brittle Deformation ◽  
Frictional Properties ◽  
Depth Extent ◽  
Mineral Constituents

Abstract Earthquake magnitude is closely related to the depth extent of the seismogenic zone, and higher magnitude earthquakes occur where the seismogenic zone is thicker. The frictional properties of the dominant mineral constituents of the crust, such as feldspar-group minerals, control the depth extent of the seismogenic zone. Here, the velocity dependence of the steady-state friction of anorthite, the calcic endmember of the feldspar mineral series, was measured at temperatures from 20 to 600 °C, pore pressures of 0 (“dry”) and 50 MPa (“wet”), and an effective pressure of 150 MPa. The results support previous findings that the frictional properties of feldspar play a dominant role in limiting the depth extent of the seismogenic zone. This evidence suggests that brittle deformation of anorthite may be responsible for brittle fault movements in the brittle–plastic transition zone.

Measurements of Loudness Growth in 1/2-Octave Bands for Children and Adults With Normal Hearing

1999 ◽  
Vol 8 (1) ◽  
pp. 40-46 ◽  
Author(s):  
Melisa R. Ellis ◽  
Michael K. Wynne
Keyword(s):  
Hearing Loss ◽  
Hearing Aids ◽  
Hearing Aid ◽  
Age Groups ◽  
Lower Boundary ◽  
Normal Hearing ◽  
Boundary Values ◽  
Simple Modification ◽  
Point Data ◽  
Loudness Growth

The loudness growth in 1/2-octave bands (LGOB) procedure has been shown previously to provide valid estimates of loudness growth for adults with normal hearing and those with hearing loss (Allen, Hall, & Jeng, 1990), and it has been widely incorporated into fitting strategies for adult hearing aid users by a hearing aid manufacturer. Here, we applied a simple modification of LGOB to children and adults with normal hearing and then compared the loudness growth functions (as obtained from end-point data) between the two age groups. In addition, reliability data obtained within a single session and between test sessions were compared between the two groups. Large differences were observed in the means between the two groups for the lower boundary values, the upper boundary values, and the range between boundaries both within and across all frequencies. The data obtained from children also had greater variance than the adult data. In addition, there was more variability in the data across test sessions for children. Many test-retest differences for children exceeded 10 dB. Adult test-retest differences were generally less than 10 dB. Although the LGOB with the modifications used in this study may be used to measure loudness growth in children, its poor reliability with this age group may limit its clinical use for children with hearing loss. Additional work is needed to explore whether loudness growth measures can be adapted successfully to children and whether these measures contribute worthwhile information for fitting hearing aids to children.

scholarly journals Strategic Analysis of the Pricing Mechanisms in an Online Book Supply Chain in the Presence of Reference Price Effects

2021 ◽  
Vol 16 (5) ◽  
pp. 1492-1516
Author(s):  
Wenhua Hou ◽  
Yuwen Zeng
Keyword(s):  
Supply Chain ◽  
Discount Rate ◽  
Reference Price ◽  
Stackelberg Game ◽  
Lower Boundary ◽  
Retail Price ◽  
Reference Points ◽  
Price Effects ◽  
Retail Prices ◽  
Online Book

(1) Background: A binding recommended retail price has been used in several markets in a variety of forms, and the book market is a typical example. Publishers sell books to online retailers at a unit wholesale discount computed on the cover price. Retailers are then allowed to set the retail price. Therefore, if consumers regard the cover prices as reference points, then they may be more likely to purchase books if retail prices are lower than the cover prices. (2) Methods: We develop a Stackelberg game model for a book supply chain to investigates how reference price effects affect retailers and publisher’s pricing strategies. (3) Results: The results show that retailers will sell printed books at a discount only when the publisher’s wholesale discount rate is not high. Further, as the intensity of the reference price effects increases, (a) the lower boundary of the wholesale discount rate rises, (b) publishers’ profits increase and (c) retailers’ profits increase relative to the level of consumers’ e-books acceptance. (4) Conclusions: This result is related to the fact that the online retailer, such as Amazon and JD.com, like to invoke reference price effects in consumers’ minds by highlighting the printed book’s discount rate.

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