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171.
Priv. Doz. Dr. Horst Treiblmaier Univ. Ass. Dr. Andreas Strebinger 《WIRTSCHAFTSINFORMATIK》2006,48(2):87-95
We analyze the influence of B2C e-commerce on IT structure and brand architecture based on conceptual considerations, a case study and an empirical survey. We first discuss the changes in transaction costs that are induced by B2C e-commerce. The effects of B2C e-commerce on IT structure and brand architecture, which are anticipated from a transaction cost perspective, are illustrated using a case study from the tourism industry. We conducted a quantitative study among 101 chief information officers (CIOs) and chief marketing officers (CMOs) from the most important consumer brand companies in Austria. The results of a correspondence analysis show that a high importance of e-commerce triggers a typical bundle of changes in IT structure and brand architecture, which point toward a stronger integration within and between these two structural elements. We therefore conclude that B2C e-commerce calls for a better coordination of those measures that impact IT structure and brand architecture. 相似文献
172.
Dipl.-Wirtsch.-Ing Michael Klafft Dr. rer. pol. Sarah Spiekermann 《WIRTSCHAFTSINFORMATIK》2006,48(1):36-45
Web-based bid invitation platforms and reverse auctions are increasingly used by consumers for the procurement of goods and
services. An empirical examination shows that with B-2-C these procurement methods generate considerable benefits for the
consumer:
相似文献
– | ⊎ Reverse auctions and bid invitation platforms generate high consumer surplus in the procurement of general and crafts services. |
– | ⊎ The level of this consumer surplus is affected by the number of bidders. The duration of the auction and the starting price are less important. |
– | ⊎ In the painting business prices are considerably lower than with traditional procurement channels. |
– | ⊎ On bid invitation platforms, in most cases (> 55%) the bids with the lowest price are chosen. |
173.
Summary This paper presents a unique approach, named mathematical regularization, to remove the nearly-singular and singular integrals occurring in the boundary integral formulations for the solution of the boundary value problems with a pathologica integration boundary due to the very near or coinciding parts of the total boundary. Nonsingular boundary integral equations are derived for thin-walled structure problems. In the case of crack-like problems, we present two kinds of the nonsingular integral representations of the secondary fields and the derivative boundary integral equations. 相似文献
174.
Dr.-Ing. B. -J. Brunsbach Univ.-Prof. Dr.-Ing. G. Henneberger Dipl.-Ing. Th. Klepsch 《Electrical Engineering (Archiv fur Elektrotechnik)》1993,76(5):335-341
Mechanische Sensoren zur Drehzahl- und Lageerfassung bei elektrischen Antrieben verursachen Kosten, vergrößern das Bauvolumen des Antriebs, bedingen die Datenübertragung zwischen Regler und Sensor und schränken das Einsatzgebiet des Antriebs ein. Daher wurden verschiedene Konzepte zum Ersatz dieser mechanischen Sensoren entwickelt. Sie unterscheiden sich durch den Aufwand, die benötigte Genauigkeit (Pumpenantrieb Servoantrieb) und dem gewünschten Betriebsbereich.In diesem Beitrag wird die Realisierung des sensorlosen Betriebs einer permanenterregten Synchronmaschine durch ein Kalman-Filter beschrieben. Durch Simulation und durch praktische Untersuchungen konnte gezeigt werden, daß die Schätzung von Lage und Drehzahl die Genauigkeitsanforderungen für eine indirekte Lageregelung erfüllt. Eine solche Lageregelung besitzt keinen mechanischen Sensor mehr. 相似文献
175.
176.
Dr. habil. N. Van Thoai 《Computing》1993,50(3):241-253
We consider a nonconvex programming problem of minimizing a linear functioncx over a convex setX?? n with an additional constraint ofmultiplicative type \(\prod _{i = 1}^p \psi _i (x) \leqslant 1\) , where the functionsψ i are convex and positive onX. The main idea of our approach is to transform this problem, by usingp additional variables, into acanonical d.c. programming problem with the special structure that thereverse convex constraint involved does only depend on the newly introduced variables. This special structure suggests modifying certain techniques in d.c. programming in a way that the operations handling the nonconvexity are actually performed in the space of the additional variables. The resulting algorithm works very well whenp is small (in comparison withn). 相似文献
177.
Report on highly automated works in Japan — management of labour in line with technology development
In recent years drastic shifts in the paradigms of politics, economics and technologies have occurred throughout the world. The shifts in these three fields are all related. It is our responsibility to investigate these shifts from the aspects of society and mankind for the prosperity of future generations. For this, societies should share with each other their wisdom and knowledge in an effort to plan for the future.Presented at conference on Ecology of Science and Technology, Japan Science Foundation, Tokyo, 1992. 相似文献
178.
Dr. P. Mazilu 《Acta Mechanica》1985,56(1-2):93-115
Summary The purpose of this work is to examine in detail the possibility to explain the decreasing of the initial shear modulus with increasing axial strain, observed first by Feigen, by means of the plastic-hypoelastic stress-strain relation suggested by Lehmann and by the author of the present paper.Notations
ij
components of the infinitesimal strain tensor dilatation
-
strain deviator
-
ij
components of the stress tensor
-
spherical part of the stress tensor
-
stress deviator
-
2=
ij
ij
second invariant of the stress deviator
-
=
33
axial strain
-
e=
13
shear component of the strain tensor
-
=2
13
shear strain
-
=
33
axial stress
-
s=
13
shear stress
-
T
ij
components of Cauchy's stress tensor
-
F
ij
components of the deformation gradient
-
L
ij
components of the velocity gradient (Eulerian coordinates)
-
components of the rate of deformation tensor
-
components of the spin tensor
-
components of the rate of deformations deviator
-
components of Cauchy's stress deviator
-
T=T
33
axial Cauchy's stress
With 7 Figures 相似文献
179.
Summary Theoretical and experimental analyses have been carried out for determining the injection condition below which the formation of air core does not take place in the course of flow of a time-independent power-law fluid through a swirl nozzle. Analytical solution lends one distinct value of generalized Reynolds number at the inlet to a nozzle below which the air core is not formed. Experiments reveal that there exist two limiting values of such generalized Reynolds number regarding the formation of air core in a nozzle. One value being the upper limit below which steady flow occurs without air core, the other one is the lower limit above which steady flow with fully developed air core persists. In between these two limiting values, there prevails a transition zone through which fully developed air core is set up within the nozzle. For all the nozzles, theoretical results are in fair agreement with the experimental values of upper limit of generalized Reynolds numbers with respect to steady flow without air core. Amongst all the pertinent independent geometrical parameters of a nozzle, the orifice-to-swirl chamber-diameter ratio has the remarkable influence on generalized Reynolds number describing the initiation of air core.Nomenclature
D
1
Swirl chamber diameter
-
D
2
Orifice diameter
-
D
s
Diameter of tangential entry ports
-
E
A non-dimensional parameter defined by Eq. (9)
-
E
R
A non-dimensional parameter defined by Eq. (25)
-
K
Flow consistency index
-
L
1
Length of the swirl chamber
-
n
Flow behaviour index
-
P
Static pressure inside the nozzle
-
P
b
Back-pressure of the nozzle
-
Q
Volume flow rate
-
R
Radius vector or longitudinal coordinate with respect to spherical coordinate system (Fig. 3)
-
R
1
Radius of the swirl chamber
-
R
2
Radius of the orifice
-
Generalized Reynolds number at the inlet to the nozzle
-
Limiting value of generalized Reynolds number describing initiation of air core
-
R
z
Radius at any section
-
r
Radial distance from the nozzle axis
-
r
a
Air core radius
-
u
Longitudinal component of velocity with respect to spherical coordinate system (Fig. 3)
-
V
r
Radial velocity component
-
V
z
Axial velocity component
-
V
Tangential velocity component
-
Tangential velocity at inlet to the nozzle
-
v
Component of velocity in the axial plane perpendicular toR (Fig. 3)
-
w
Component of velocity perpendicular to axial plane with respect to the spherical coordinate system (Fig. 3)
-
z
Distance along the nozzle axis from its inlet plane
-
Half of the spin chamber angle
-
Boundary layer thickness measured perpendicularly from the nozzle wall
- 2
Boundary layer thickness at the orifice
-
Angle, which a radius vector makes with the nozzle axis, in spherical coordinate system (Fig. 3)
-
Density of the fluid
-
Running coordinate in the azimuthal direction with respect to the cylindrical polar coordinate system as shown in Fig. 3
-
Circulation constant
With 8 Figures 相似文献
180.
Dr. R. Haverkamp 《Computing》1984,32(4):343-355
Letp n denote the polynomial of degreen or less that interpolates a given smooth functionf at the ?eby?ev nodest j n =cos(jπ/n), 0≤j≤n, and let ‖·‖ be the maximum norm inC[?1, 1]. It is proved that fork-th derivatives (2≤k≤n) estimates of the following type hold $$\parallel f^{(k)} - p_n^{(k)} \parallel \leqslant c_k n^{k - 1} \inf \{ \parallel f^{(k)} - q\parallel :q \in \Pi _{n - k} \} .$$ In this relationc k only depends onk andΠ n?k denotes the space of polynomials up to degreen?k. 相似文献