scholarly journals Complexity of matrix organization and problems caused by its inadequate implementation

2007 ◽  
Vol 52 (174-175) ◽  
pp. 28-44 ◽  
Author(s):  
Nebojsa Janicijevic ◽  
Ana Aleksic

Matrix organization model is a sophisticated structure intended to combine both the efficiency and effectiveness of the functional and the product/service/customer/area dimensions. From the moment it was introduced in practice, this organizational architecture was accepted with enthusiasm, because it represented a complex organizational response adequate to the conditions which most of the companies in the world have been facing since 1970s. Although matrix organization is not a novelty, it is still a controversial model of organization design. The aim of this paper is to provide a deeper insight into the causes and effects of organizational misfits which appear in the implementation phase of three-dimensional matrix organization, as well as to offer some practical recommendations for managers on how to improve their capacities for successful management of complex matrix organization architecture in their organizations.

2017 ◽  
Vol 2017 ◽  
pp. 1-16 ◽  
Author(s):  
Gayathri Subramanian ◽  
Alexander Stasuk ◽  
Mostafa Elsaadany ◽  
Eda Yildirim-Ayan

Adipose-derived mesenchymal stem cells have become a popular cell choice for tendon repair strategies due to their relative abundance, ease of isolation, and ability to differentiate into tenocytes. In this study, we investigated the solo effect of different uniaxial tensile strains and loading frequencies on the matrix directionality and tenogenic differentiation of adipose-derived stem cells encapsulated within three-dimensional collagen scaffolds. Samples loaded at 0%, 2%, 4%, and 6% strains and 0.1 Hz and 1 Hz frequencies for 2 hours/day over a 7-day period using a custom-built uniaxial tensile strain bioreactor were characterized in terms of matrix organization, cell viability, and musculoskeletal gene expression profiles. The results displayed that the collagen fibers of the loaded samples exhibited increased matrix directionality with an increase in strain values. Gene expression analyses demonstrated that ASC-encapsulated collagen scaffolds loaded at 2% strain and 0.1 Hz frequency showed significant increases in extracellular matrix genes and tenogenic differentiation markers. Importantly, no cross-differentiation potential to osteogenic, chondrogenic, and myogenic lineages was observed at 2% strain and 0.1 Hz frequency loading condition. Thus, 2% strain and 0.1 Hz frequency were identified as the appropriate mechanical loading regime to induce tenogenic differentiation of adipose-derived stem cells cultured in a three-dimensional environment.


2021 ◽  
Vol 8 (1) ◽  
pp. 205395172110135
Author(s):  
Florian Jaton

This theoretical paper considers the morality of machine learning algorithms and systems in the light of the biases that ground their correctness. It begins by presenting biases not as a priori negative entities but as contingent external referents—often gathered in benchmarked repositories called ground-truth datasets—that define what needs to be learned and allow for performance measures. I then argue that ground-truth datasets and their concomitant practices—that fundamentally involve establishing biases to enable learning procedures—can be described by their respective morality, here defined as the more or less accounted experience of hesitation when faced with what pragmatist philosopher William James called “genuine options”—that is, choices to be made in the heat of the moment that engage different possible futures. I then stress three constitutive dimensions of this pragmatist morality, as far as ground-truthing practices are concerned: (I) the definition of the problem to be solved (problematization), (II) the identification of the data to be collected and set up (databasing), and (III) the qualification of the targets to be learned (labeling). I finally suggest that this three-dimensional conceptual space can be used to map machine learning algorithmic projects in terms of the morality of their respective and constitutive ground-truthing practices. Such techno-moral graphs may, in turn, serve as equipment for greater governance of machine learning algorithms and systems.


1993 ◽  
Vol 183 (1) ◽  
pp. 217-248 ◽  
Author(s):  
S. Sunada ◽  
K. Kawachi ◽  
I. Watanabe ◽  
A. Azuma

A series of experiments on three-dimensional ‘near fling’ was carried out. Two pairs of plates, rectangular and triangular, were selected, and the distance between the rotation axes of the two plates of each pair was varied. The motion of the plates as well as the forces and the moment were measured, and the interference between the two plates of a pair was studied. In addition, a method of numerical calculation was developed to aid in the understanding of the experimental results. The interference between the two plates of a pair, which acted to increase both the added mass of each plate and the hydrodynamic force due to dynamic pressure, was noted only when the opening angle between the plates was small. The hydrodynamic forces were strongly influenced by separated vortices that occurred during the rotation. A method of numerical calculation, which took into account the effect both of interference between the plates and of separated vortices, was developed to give adequate accuracy in analyzing beating wings in ‘near fling’.


Author(s):  
Peter Racioppo ◽  
Wael Saab ◽  
Pinhas Ben-Tzvi

This paper presents the design and analysis of an underactuated, cable driven mechanism for use in a modular robotic snake. The proposed mechanism is composed of a chain of rigid links that rotate on parallel revolute joints and are actuated by antagonistic cable pairs and a multi-radius pulley. This design aims to minimize the cross sectional area of cable actuated robotic snakes and eliminate undesirable nonlinearities in cable displacements. A distinctive feature of this underactuated mechanism is that it allows planar serpentine locomotion to be accomplished with only two modular units, improving the snake’s ability to conform to desired curvature profiles and minimizing the control complexity involved in snake locomotion. First, the detailed mechanism and cable routing scheme are presented, after which the kinematics and dynamics of the system are derived and a comparative analysis of cable routing schemes is performed, to assist with design synthesis and control. The moment of inertia of the mechanism is modeled, for future use in the implementation of three-dimensional modes of snake motion. Finally, a planar locomotion strategy for snake robots is devised, demonstrated in simulation, and compared with previous studies.


Anduli ◽  
2021 ◽  
pp. 235-251
Author(s):  
Marta Pérez-Castro

Relationships among visual signs, society and memory reveal the dominant cultural order in a given context as well as the causes that maintain it (influence and imposition) and the effects on the population where it occurs (alienation and cultural resilience). Therefore, it is possible to identify deeper social processes with a purely visual and symbolic reading. Visual signs (two-dimensional), in addition to configuring the way space is understood (three-dimensional), reflect social and political dynamics (the time factor). To have a more complete vision of the moment and context, it is necessary to interrelate art with sociology and history. In the specific case of al-Andalus, there is a turning point at which there are changes in visuality that are mainly reflected in writing (Arabic and Latin), the use of symbols (the Mudejar, the cross) and the organization of the spaces designated for art (temples, museums, exhibition halls); hence, these changes function as visual indexes of social dynamics that reach to the present day. The visual supports the social and vice versa, configuring and maintaining a certain worldview. If there is visual continuity, there is continuity in the social sphere.


1995 ◽  
Vol 32 (6) ◽  
pp. 976-988 ◽  
Author(s):  
G.J.W. King ◽  
M. Laman

An experimental investigation into the moment carrying capacity of short rigid pier foundations in saturated clay is described. Scale models of square piers with different breadths and depths were used in both conventional and centrifugal studies. The results show that the relationships between moment and rotation are nonlinear but do not exhibit any peak values, and that moment limits, defined by limiting angular rotations, increase with increases in pier depth and breadth. Empirical equations are derived between moment carrying capacity and pier geometry, for a range of limiting rotations, and a very close fit is demonstrated between the moment–rotation relationships obtained using these equations and the actual data obtained from the model tests. It is shown that, at the same pier rotations, the moment carrying capacities observed in the centrifugal model tests are significantly larger than those in the conventional model tests. Numerical analyses of the prototype geometries were also carried out using a three-dimensional nonlinear finite-element computer program. The results are shown to provide satisfactory agreement with the moment–rotation behaviour and working limits observed in the centrifuge model tests. Thus, even though conventional modelling is usually legitimate for determining the immediate bearing capacity of rigid foundations in saturated clay, their rotational stability is shown to be significantly affected by self-weight stresses. Some of the existing methods for designing short piers subjected to moments are examined and compared with the results from the centrifuge model tests. Key words : pier foundation, clay, moment capacity.


Over 1500 lunar laser range measurements have been made during the past six years at McDonald Observatory. These data have been fitted with a 41 cm r. m. s. residual. The geocentric coordinates of McDonald Observatory are now known to better than 1 m, the three-dimensional coordinates of the Moon and the selenocentric coordinates of the retroreflectors are accurate to about 25 m, and the mass ratio Sun/(Earth + Moon) is determined to 2 parts in 107. A search for the Nordtvedt term in the Moon’s orbit, a term predicted by some relativity theories, gives a null value, a result consistent with general relativity. The measurement of the physical librations determines very accurately the moment of inertia parameters β = (C - A)/B and γ = (B - A)/C, and significantly determines the third degree gravitational harmonics C 30 , C 32 , S 32 and S 33 The postfit residuals are not random but yield corrections to the rotation of the Earth, values of U. T. 0 for individual days having typical accuracies of 0.5 ms (20cm). The anticipated regular operation of two or more stations will allow the separation of U. T. 1 and polar motion.


2020 ◽  
Vol 20 (07) ◽  
pp. 2071005
Author(s):  
Y. B. Yang ◽  
Y. Z. Liu

Lateral buckling of cantilevered circular arches under various end moments is studied using an analytical approach. Three types of conservative moments are considered, i.e. the quasi-tangential moments of the 1st and 2nd kinds, and the semi-tangential moment. The induced moments associated with each of the moment mechanisms undergoing three-dimensional rotations are included in the Newman boundary conditions. Using the differential equations available for the out-of-plane buckling of curved beams, the analytical solutions are derived for a cantilevered circular arch, which can be used as the benchmarks for calibration of other methods of analysis.


2017 ◽  
Vol 87 (5) ◽  
pp. 774-781 ◽  
Author(s):  
Andrea Wichelhaus

ABSTRACT Objective: To biomechanically test a new elastic slot system and V-wire mechanics. Materials and Methods: Conventional twin and self-ligating brackets and the new elastodynamic bracket were biomechanically tested. The conventional brackets had a rectangular 0.022′′ slot and the new elastodynamic bracket had a V-slot, a new slot geometry. Torque measurements were performed with 0.018′′ × 0.025′′ and 0.019′′ × 0.025′′ stainless steel (ss) archwires. A nickel-titanium V wire was used for the biomechanical measurements on the elastodynamic bracket. The measurements were done with the aid of a six-component measuring sensor. Results: The results of the biomechanical testing revealed play in the brackets with rectangular slot geometry. The V slot in the elastodynamic bracket assured that the wire fit perfectly in the slot. Dynamic moments of 5 to 10 Nmm were transmitted without any play. No permanent deformation of the slot occurred in the new elastodynamic bracket because of the elastic slot. Conclusion: Control of torque for three-dimensional positioning of the teeth in the dental arch with rectangular slot geometry as used in straight-wire therapy is difficult. If torque is bent into the wire, because of the play there is a high risk that either too much, too little, or no moment is transmitted to the teeth. The V-slot archwire/bracket geometry in conjunction with nickel titanium composition has no play and allows a reduction of forces and moments with direct and continuous transmission of torque in the bracket. Because of the elasticity of the bracket, there is an upper limit to the moment possible.


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