Mathematical and Computational Applications

1332 KiB

Open AccessArticle

Using the Growth Models for Optimization of Energy Distributions Systems

by Fahri Okan Pekiner

Math. Comput. Appl. 1996, 1(2), 169-173; https://doi.org/10.3390/mca1020169 - 01 Dec 1996

Viewed by 1209

Energy distribution systems were developed in the recent years due to increasing population, new technologies and load demand. Alternative technical arrangements are made trouble to choose the best construction. On the other hand, system costs are affected for the new design and operating. That is, for [...] Read more.

Energy distribution systems were developed in the recent years due to increasing population, new technologies and load demand. Alternative technical arrangements are made trouble to choose the best construction. On the other hand, system costs are affected for the new design and operating. That is, for a new distribution design or operation of an exist syatem, both technical and economical constraints must be consider. [...] Full article

1328 KiB

Open AccessArticle

The Finite Element Analysis of Buckling of Laminated Rectangular Reinforced Concrete Plates with Circular Hole

by Muhammed D. Tekin and M. Fatih Altan

Math. Comput. Appl. 1996, 1(2), 164-168; https://doi.org/10.3390/mca1020164 - 01 Dec 1996

Cited by 1 | Viewed by 1292

Abstract

In this investigation an approach buclcling analysis for simply supported rectangular reinforced concrete plates under uniaxial compression are developed. The objective of this investigation is to compare buclcling load of the reinforced plate with circular hole and without hole. A laminated composite plate [...] Read more.

In this investigation an approach buclcling analysis for simply supported rectangular reinforced concrete plates under uniaxial compression are developed. The objective of this investigation is to compare buclcling load of the reinforced plate with circular hole and without hole. A laminated composite plate is considered.The finite element models for with central circular hole and without hole are designed. The composite materials and composite laminates materials approach are discussed. The solution of the problem by computer program coded in FORTRAN is explained and numerical example is given. Full article

2626 KiB

Open AccessArticle

Finite Element Modeling of Drillstrings

by A. S. Yigit, M. D. Al-Ansary and M. Khalid

Math. Comput. Appl. 1996, 1(2), 158-163; https://doi.org/10.3390/mca1020158 - 01 Dec 1996

Cited by 1 | Viewed by 1236

Abstract

A finite element model is presented for investigating dynamic behavior of drillstrings used in oil and gas wells. A Timoshenko beam element is used to model axial and transverse vibrations. The effect of axial load, gravity, the constraints due to stabilizers are considered. [...] Read more.

A finite element model is presented for investigating dynamic behavior of drillstrings used in oil and gas wells. A Timoshenko beam element is used to model axial and transverse vibrations. The effect of axial load, gravity, the constraints due to stabilizers are considered. The results show that a small amount of disorder in the configuration as well as the gravity cause strong mode localization which may be catastrophic. The implications for design and operation in the presence of mode localization is also discussed. Full article

3033 KiB

Open AccessArticle

Relation between Darboux Instantaneous Rotation Vectors of Curves on Time-Like Surface

by H. Hüseyin Uğurlu and Ali Topal

Math. Comput. Appl. 1996, 1(2), 149-157; https://doi.org/10.3390/mca1020149 - 01 Dec 1996

Cited by 1 | Viewed by 1258

Abstract

In this study, a fundamental relation, as a base for the geometry of the time-like surfaces, among the Darboux vectors of an arbitrary time-like curve (c) on a time-like surface and the parameter curves (c₁) and (c₂) in the [...] Read more.

In this study, a fundamental relation, as a base for the geometry of the time-like surfaces, among the Darboux vectors of an arbitrary time-like curve (c) on a time-like surface and the parameter curves (c₁) and (c₂) in the Minkowski 3-space R₁³ was founded. Full article

2353 KiB

Open AccessArticle

The Study Mapping for Directed Space-Like and Time-Like in Minkowski 3-Space R13

by H. Hüseyin Uğurlu and Ali Çalışkan

Math. Comput. Appl. 1996, 1(2), 142-148; https://doi.org/10.3390/mca1020142 - 01 Dec 1996

Cited by 10 | Viewed by 1388

Abstract

In this study, the E. Study mapping was dermed for the space-like and time-like lines in the Minkowski 3-space R₁³. Hence, there is one to one correspondence between directed space-like (resp., time-like) lines of R₁³ and ordered pair [...] Read more.

In this study, the E. Study mapping was dermed for the space-like and time-like lines in the Minkowski 3-space R₁³. Hence, there is one to one correspondence between directed space-like (resp., time-like) lines of R₁³ and ordered pair of vectors (a,a₀.) such that < a,a> = 1 (resp., < a,a> = -1) and <a,a₀> = 0. Full article

2818 KiB

Open AccessArticle

The Frenet and Darboux Instantaneous Rotation Vectors of Curves on Time-Like Surface

by H. Hüseyin Uğurlu and Hüseyin Kocayiğit

Math. Comput. Appl. 1996, 1(2), 133-141; https://doi.org/10.3390/mca1020133 - 01 Dec 1996

Cited by 4 | Viewed by 1320

Abstract

In this paper, depending on the Darboux instantaneous rotation vector of a solid perpendicular trihedron in the Minkowski 3-space [...] Full article

2843 KiB

Open AccessArticle

A Cost-Effective Method for Ultrasound Volumetric Imaging

by F. Nazan Uçar and Mustafa Karaman

Math. Comput. Appl. 1996, 1(2), 127-132; https://doi.org/10.3390/mca1020127 - 01 Dec 1996

Viewed by 1246

Abstract

A synthetic receive aperture technique is explored for cost-effective ultrasound scanners with high frame rates and beam density. The technique provides ultrasound volumetric imaging where beam count is very large with 2-D transducer arrays using subaperture processing. For every beam line, transmit beam [...] Read more.

A synthetic receive aperture technique is explored for cost-effective ultrasound scanners with high frame rates and beam density. The technique provides ultrasound volumetric imaging where beam count is very large with 2-D transducer arrays using subaperture processing. For every beam line, transmit beam is performed with a small subaperture whereas the reflected echo signals are received from non-overlapping subapertures. For every transmit-receive subaperture combination, a small number of beams are acquired and then the number of beam lines is increased through beam space interpolation. A 2-D linear filter with a different spatial frequency band for each subaperture is employed as the interpolation filter. Performance of the technique is analyzed through simulations. The technique reduces the number of firings and therefore allows real-time imaging with very low susceptibility to motion artifacts. Full article

5260 KiB

Open AccessArticle

A Comparative Study of Existing Manufacturing, Planning and Control Approaches

by O. Torkul, I. H. Cedimoğlu and M. S. Aksoy

Math. Comput. Appl. 1996, 1(2), 117-126; https://doi.org/10.3390/mca1020117 - 01 Dec 1996

Viewed by 1135

Abstract

During the 1980s various approaches to batch-type manufacturing environments were implemented. The most popular of these were Material Requirements Planning (MRP), Group Technology (GT) and Just-In-Time (JIT). However few successful implementations of any of these approaches were achieved [1] [2] [3]. This paper [...] Read more.

During the 1980s various approaches to batch-type manufacturing environments were implemented. The most popular of these were Material Requirements Planning (MRP), Group Technology (GT) and Just-In-Time (JIT). However few successful implementations of any of these approaches were achieved [1] [2] [3]. This paper compares the various approaches of GT, MRP, JIT along with the integrated approaches such as MRP/GT and MRP/JIT. Full article

3373 KiB

Open AccessArticle

On the Partial Generalization of the Measure of Transcendence of Some Formal Laurent Series

by Ahmet Ş. Özdemir

Math. Comput. Appl. 1996, 1(2), 100-110; https://doi.org/10.3390/mca1020100 - 01 Dec 1996

Viewed by 1382

Abstract

In this work, we determine the trallscendence measure of the formal Laurent series "that" [...] Full article

2381 KiB

Open AccessArticle

Buckling of Heavy Bars

by Ing. Aydoğan Özdamar

Math. Comput. Appl. 1996, 1(2), 93-99; https://doi.org/10.3390/mca1020093 - 01 Dec 1996

Viewed by 1200

Abstract

The calculation for the buckling of a short bar under compression occurs normally through the neglect of its own weight. This method is no longer permissible for long heavy bars. In this case, the net weight must be taken into consideration. Such long [...] Read more.

The calculation for the buckling of a short bar under compression occurs normally through the neglect of its own weight. This method is no longer permissible for long heavy bars. In this case, the net weight must be taken into consideration. Such long heavy bars can be found, for example, as drilling-risers in ocean exploration technology, as schafts in mining, as steel turrets for the production of energy and as naturally grown mammoth trees.

In this paper, the critical buckling forces are derived from ten end conditions for heavy bars which are surrounded by air and burdened by compression. There is an analytical solution to the differential equation of the problem which requires a numerical evaluation. Limited computer capacity permits calculations of critical buckling forces only up to a certain length. An analytical solution to the differential equation must be developed asymptotically for long heavy bars. With the help of this asymptotic evaluation, the critical buckling forces for long heavy bars are found. Full article

2977 KiB

Open AccessArticle

Minimum Permeance Estimation of Variable Reluctance Machines by Using Neural Networks

by Erkan Mese

Math. Comput. Appl. 1996, 1(2), 87-92; https://doi.org/10.3390/mca1020087 - 01 Dec 1996

Viewed by 1251

Abstract

A new approach was studied in this paper to calculate minimum permeance (Pmin) of variable reluctance machines (VRM). Finite element method (FEM) and neural network (NN) were employed together for estimation. The data collected by an electromagnetic finite element software (Flux 2D) were [...] Read more.

A new approach was studied in this paper to calculate minimum permeance (Pmin) of variable reluctance machines (VRM). Finite element method (FEM) and neural network (NN) were employed together for estimation. The data collected by an electromagnetic finite element software (Flux 2D) were used to train NN. Trained NN was tested by another data set which are not in the training data set. Total estimation error in the test set was observed less than 2.5%. A similar study was performed with the data set collected using flux tube analysis (FTA). In this case, much larger data set was constructed by FTA since this method allows to generate larger data set. After training NN by this data set, it was tested by a test set generated by FTA. The total estimation error was observed less than 5%. Full article

3271 KiB

Open AccessArticle

The Frenet and Darboux Instantaneous Rotation for Curves on Space-Like Surface

by Osman Kılıç and Ali Çalışkan

Math. Comput. Appl. 1996, 1(2), 77-86; https://doi.org/10.3390/mca1020077 - 01 Dec 1996

Cited by 1 | Viewed by 1299

Abstract

In this paper , considering the Darboux instantaneous rotation vector of a solid perpendicular trihedron in the Minkowski 3-space R₁³, the Frenet instantaneous rotation vector was stated for the Frenet trihedron of a space -like space curve (c) with the [...] Read more.

In this paper , considering the Darboux instantaneous rotation vector of a solid perpendicular trihedron in the Minkowski 3-space R₁³, the Frenet instantaneous rotation vector was stated for the Frenet trihedron of a space -like space curve (c) with the binormal b being a time-like vector. The Darboux derivative formulas and the Darboux instantaneous rotation vector were found when the curve (c) is on a space -like surface. A fundamental relation, as a base for the geometry of space-like surfaces, was obtained among the Darboux vectors of the parameter curves (c₁) , (c₂) and an arbitrary curve (c) on a space-like surface. Full article

2428 KiB

Open AccessArticle

Reconstruction with Computerized Microwave Diffraction Tomography by Using Circular Measurement System in the Far-Field Region

by Sedef Kent and Bingül Yazgan

Math. Comput. Appl. 1996, 1(2), 71-76; https://doi.org/10.3390/mca1020071 - 01 Dec 1996

Viewed by 1093

Abstract

This paper deals with far-field microwave imaging of a dielectric object satisfying the Born approximation. The results of computer simulations obtained with a circular measuring geometry are given. The computational efficiency of this method is also shown. Full article

9163 KiB

Open AccessArticle

Symmetries of Nonlinear Telegraph Equations in Strong Fields

by G. Haager, G. Baumann and T. F. Nonnenmacher

Math. Comput. Appl. 1996, 1(2), 47-70; https://doi.org/10.3390/mca1020047 - 01 Dec 1996

Viewed by 1185

Abstract

In this article the symmetries of a class of nonlinear telegraph equations are examined. These equations represent a physical model describing electro magnetic shock waves. The main interest is concentrated on potential symmetries but Lie point and non classical symmetries are also calculated. [...] Read more.

In this article the symmetries of a class of nonlinear telegraph equations are examined. These equations represent a physical model describing electro magnetic shock waves. The main interest is concentrated on potential symmetries but Lie point and non classical symmetries are also calculated. With the aid of these symmetries explicit new solutions are derived or given implicitly by defining equations. Full article

1724 KiB

Open AccessArticle

A New Algorithm to Obtain δ-Operator Based Transfer Function From Its Continuous Time Counterpart

by Omer Gundogdu

Math. Comput. Appl. 1996, 1(2), 42-46; https://doi.org/10.3390/mca1020042 - 01 Dec 1996

Viewed by 1157

Abstract

This paper discusses the advantages of the δ-operator over the forward shift operator q in implementation of discrete-time systems. The δ-operator gives better coemcient representation and less round-off noise in many cases. As an application, a new algorithm is introduced here to obtain [...] Read more.

This paper discusses the advantages of the δ-operator over the forward shift operator q in implementation of discrete-time systems. The δ-operator gives better coemcient representation and less round-off noise in many cases. As an application, a new algorithm is introduced here to obtain δ-operator based transfer functions from continuous time counterparts, Finally, a ourth-order Butterworth low-pass filter is taken as an example tocompare coeffcient sensitivity effects of q- and δ-operator systems. Full article

3286 KiB

Open AccessArticle

Experimetntal Detection of the Faults in a Gearbox

by Ekrekli A., Güçlü R. and Tahralı N.

Math. Comput. Appl. 1996, 1(2), 35-41; https://doi.org/10.3390/mca1020035 - 01 Dec 1996

Viewed by 1429

Abstract

Dynamic analysis of gearboxes especially driven at high speeds has always been an area of interest for researchers. It is important to know the dynamic behaviour of a gearbox to operate it more efficiently from the friction and vibration point of views. This [...] Read more.

Dynamic analysis of gearboxes especially driven at high speeds has always been an area of interest for researchers. It is important to know the dynamic behaviour of a gearbox to operate it more efficiently from the friction and vibration point of views. This is important for the automotive industry. To evaluate the vibration of gearboxes produced by a military factory based in Tuzla, an accelerometer is used together with an amplifier and an A/D converter fitted in the computer. Nonrecursive digital filtering programmed by the authors manifested the contribution of vibration from each part of the gearbox. Full article

2735 KiB

Open AccessArticle

Segmentation of Ultrasonic Images Using Fuzzy Sets

by H. Çelebi, M. Gündüzalp and M. Karaman

Math. Comput. Appl. 1996, 1(2), 29-34; https://doi.org/10.3390/mca1020029 - 01 Dec 1996

Viewed by 1179

Abstract

Full article

3483 KiB

Open AccessArticle

Improved Part Modeling in a Process Planning System

by Ali Çalışkan, Bahadlr Tantay and Filiz Yağcı

Math. Comput. Appl. 1996, 1(2), 21-28; https://doi.org/10.3390/mca1020021 - 01 Dec 1996

Viewed by 1299

Abstract

An expert process planning and fixturing system described in [14] is improved here by applying Boolean operations. This system uses forward planning strategy, i.e. begins with the blank part and applies some operations for each face or feature until reaching the finished part. [...] Read more.

An expert process planning and fixturing system described in [14] is improved here by applying Boolean operations. This system uses forward planning strategy, i.e. begins with the blank part and applies some operations for each face or feature until reaching the finished part. This paper is focused on finished and intermediate part modeling within the process planning system by geometric transformations and Boolean operations. Full article

2562 KiB

Open AccessArticle

Determination Of Yield Strenght of 2014 Aluminium Alloy under Aging Conditions by Means of Artifical Neural Networks Method

by Enver AtiK, Cevdet Meriç and Bekir Karlik

Math. Comput. Appl. 1996, 1(2), 16-20; https://doi.org/10.3390/mca1020016 - 01 Dec 1996

Cited by 2 | Viewed by 1463

Abstract

As known, 2XXX and 7XXX Aluminum process alloys can have high strength values by means of precipitation hardening heat treatment. Determination of the precipitation hardening conditions which can give the most suitable strength values of an alloy, requires numerous tests. But the results [...] Read more.

As known, 2XXX and 7XXX Aluminum process alloys can have high strength values by means of precipitation hardening heat treatment. Determination of the precipitation hardening conditions which can give the most suitable strength values of an alloy, requires numerous tests. But the results of this process which require long time and high cost can be obtained in a shorter time and at a lower cost with less data by means of Artificial Neural Networks method. Since this method is used, less number of experiments and therefore less data is needed. Then other values are found by means of Artificial Neural Networks method.In this study, Artificial Neural Networks were educated with yield strength values of 2014 Aluminum alloy obtained at different aging times and at 150, 190, 232, and 260 °C after taken into solution at 500 °C. Afterwards, yield strengths of alloy at different temperatures were
determined by means of Artificial Neural Networks method. Full article

3253 KiB

Open AccessArticle

The Group of Twist Knots

by Yılmaz Allin and Mehmet Emin Bozhüyük

Math. Comput. Appl. 1996, 1(2), 7-15; https://doi.org/10.3390/mca1020007 - 01 Dec 1996

Cited by 1 | Viewed by 1307

Abstract

In this paper some interesting invariants of twist knots are calculated. Especially the first homotopy and the first homology groups of all three sheeted branched covering spaces of the three dimensional sphere branched over twist knots are given. Full article

2643 KiB

Open AccessArticle

A New Technique to Process and Recognize Barcodes Using Induction

by M. S. Aksoy and M. Bayram

Math. Comput. Appl. 1996, 1(2), 1-6; https://doi.org/10.3390/mca1020001 - 01 Dec 1996

Viewed by 1360

Abstract

In this paper, a new technique to recognize and process Barcodes is introduced. The technique employs Inductive Learning. It is suitable to use, for example, in a factory to control the workers, staff, stock etc. In this technique only vertical lines are considered [...] Read more.

In this paper, a new technique to recognize and process Barcodes is introduced. The technique employs Inductive Learning. It is suitable to use, for example, in a factory to control the workers, staff, stock etc. In this technique only vertical lines are considered while the spaces in between are ignored. This results faster processing. Each Barcode is considered to represent an item. For each Barcode a rule is extracted from the necessary information using Inductive Learning. So the unnecessary information is eliminated. This causes faster processing time and less amount of memory. In order to use this technique no special hardware is required. Only a PC and a Barcode reader is enough. Full article

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Math. Comput. Appl., Volume 1, Issue 2 (December 1996) – 21 articles , Pages 1-173

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