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APPLIED RESEARCH REVIEW Journal of the Technological Education
Institute of Piraeus
VL. VI No 1 2003 ISSN - 1106 - 4110
. PRIMENTAS: The spiral distortion of single jersey tubular
knitted fabricsI. Description of the effect . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . .5
F. KOMISSOPOULOS, G. GAGALIS: E-learning in Greece:
The right content for the right purpose . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
.17
. : : 1990-2000 . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . .35
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. . . . . . . . . . . . . . . . . .111
A. VASSILIADIS, M. ROULIA: Application of C.I. Disperse Blue
56to Poly(p-phenyleneterephthalamide) Fibers . . . . . . . . . . .
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Copyright TEI 2003
. 250
122 44
.: 210.53.81.100
ISSN - 1106 - 4110
-
APPLIED RESEARCH REVIEW
fi 250, 122 44
Journal of the Technological Education Institute of Piraeus250,
Thivon str. 122 44 Egaleo, Greece
, fi fi / fi fi /
:
DITORIAL COMMITTEE
Kikilias Panayiotis TEI of Piraeus, PresidentAntoniou Solon TEI
of PiraeusGoudas Constantine University of PatraDiamadopoulos
Dimitris TEI of PiraeusExarchakos Theodoros University of
AthensCantzos Constantine TEI of PiraeusKontesis Michalis TEI of
PiraeusKoronakis Periclis TEI of PiraeusBleris Georgios University
of Thessaloniki
Secretary: Kermeli Evangelia
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The spiral distortion of single jersey tubularknitted fabricsI.
Description of the effect
Anthony PrimentasDepartment of Textile Engineering... of
Piraeus
Abstract
Most of the single jersey weft knitted fabrics suffer from wales
distortion that result inthe spiral appearance of the knitted
goods. This defect is called spirality and causes greattrouble to
the knitted garment manufacturers. In this article, among the
detailed exami-nation of the nature, the origins and the
characteristics of the spirality effect, the distinc-tion between
the spirality and the drop effect is attempted.
fi fi fi fi , fi fi. fi - . fi, , fi -.
The spiral distortion of single jersey tubular knitted fabrics.
I. Description... 5
Vol. VIII, No 1, 2003, pp. 5-16
-
1. The nature of spirality
In many tension-free, tubular single-yarn fabrics, knitted in a
plain stitch on a circularone needle system knitting machine, the
lengthwise rows of loops (stitches) called needlelines or wales,
should normally occupy a truly vertical line, parallel to the edges
of the fab-ric and at right angles (90) to the crosswise rows of
loops called courses, when the fabricis undistorted. In practice,
however, an undesirable phenomenon becomes vividly appar-ent, where
the wales show a pronounced bias towards the left or the right
[Nutting, 1960,Buhler & Haussler, 1981, Araujo & Smith,
1989]. This fault occurs particularly in singlejersey knitted
fabrics and garments where a dissymmetry of the loop between the
face andback of the fabric becomes visible [Anon., 1980]. This
results in seams that do not run par-allel to the edges of garment
made up from such material, although the line of courses re-mains
perpendicular to the edges of the fabric. This defect has been
appropriately termedby Davis et al. (1934) as spirality, since it
occurs chiefly in tubular fabrics, where thewales follow a spiral
path around the axis of the fabric, forming an angle with the
per-pendicular (Figure 1). The comparable defect on a flat knitted
fabric is referred to as walespirality [Textile Institute, 1995]
where the wales follow a sideways direction forming anangle with
the perpendicular. This angle is termed as the spirality angle and
is a meas-ure of the fabric spirality [Stevens, 1985].
Figure 1: Spirality of a knitted fabric
If the loops of each course on the technical face of a knitted
fabric are examined close-ly, an inclination to lean slightly to
the right (or left) is observed, indicating an excess ofyarn on the
left or right hand side respectively of the loop, i.e., the
formation of each loopis just a little lopsided [Hughes, 1945]. The
lifting of the one side of the knitted loop fromthe plane of the
fabric is the cause of the appearance of an almost rib-like
structure form,as the wales are bunched together [Nutting,
1960].
When the fabric is on a knitting machine, the magnitude of this
distortion is unpre-dictable because of the imposition of strains
on it due to the take-down tension [Charnock,
6 E E E , Vol VIII, No 1, 2003
-
1977]. As the fabric is released from the stress due to this
tension, a complete change oc-curs in the shape of each of its unit
cells (loops). This rearrangement of the fabric structureresults in
an initial fabric distortion. If the fabric undergoes a process of
wetting (immers-ing in water, dyeing, washing), there is a further
distortion of the fabric which is mainly aresult of reappearance of
the forces in the yarn which have been relaxed in the earliersteam
setting of yarn [Fletcher & Roberts, 1953]. This factor must be
recognised in pro-ducing a commercially acceptable washable
product.
Stacey (1951), Parker (1981), Buhler & Haussler (1985),
Haigh (1987) and Oinuma &Takeda (1988) who dealt with this
phenomenon of spirality agree that the main reasonfor this defect
is the unbalanced torque within the yarn, shown by its
twist-liveliness,the release of torsional potential energy in the
yarn, rather than just the presence of thetwist alone. In
combination with the unbalanced active torque in the yarn, there is
thecontribution of fabric geometry. The degree of freedom of yarn
movement in the fabricstructure contributes significantly to the
rise of spirality [Nutting, 1971]. The more slackthe fabric
structure, the greater the spirality. This slackness can be
achieved by two ways:by changing the tightness factor or, by
changing the linear density of the yarn. Haigh(1987) has stated
that the loop twisting, over to approximately the same angle as the
spi-rality angle, is the result of the section of yarn in each loop
that is trying to move to astate of lower strain under the
constraint of forces from neighbouring loops. Leaf &Glaskin
(1955) and Munden (1959) have shown that much of this distortion
arises fromthe residual torque in the yarn. Newly produced ring
spun yarns exhibit a tremendoustendency to untwist, before being
treated with any dry or wet relaxation method. Thisphenomenon could
be explained by taking into consideration that, elastic stresses as
welltorsional forces (torque), set up in the component fibres by
the twisting action during thespinning process, attempt to be
relieved. This tends to cause an opening up of the yarnand gives
raise to yarn and fabric defects (e.g., snarls, spirality,
cockling) [Anon., 1980].Hence, the greater the twist-liveliness,
the greater the spirality [Nutting, 1960]. At thispoint it is
necessary to mention that, although this statement is generally
acceptable, itwas found in the literature that there is confusion
between the twist amount in the yarnand the yarn torque [Davis et
al. 1934, Dutton, 1951]. Some statements that reflect this,are
given below:...the degree of spirality is related to the twist
factor (number of turns per length of the
yarn) [Brackenbury, 1992]; Yarns with lower turns per unit
length, tend to develop less spirality in the fabric than
yarns with high twist levels... [Stevens, 1985]....spirality
increases with the turns per inch ... [Davis & Edwards
1935];...spirality is often due to an excess amount of twist in the
yarn from which the fabric is
knitted... [Roytowski, 1972];
The spiral distortion of single jersey tubular knitted fabrics.
I. Description... 7
-
2. Direction of spirality
It is well known that the yarn twist direction determines the
direction of the spiralityin fabrics knitted from singles short
staple yarns. Thus, if a Z-twisted yarn is been knittedto produce a
single jersey fabric, the technical face of the fabric exhibits
spirality in the Zdirection and vice versa [Buhler & Haussler
1985] (Figures 1,2).
Z-spirality S-spirality
Figure 2: Spirality direction of knitted fabrics
3. Measurement of spirality
The angle of spirality can be measured with the help of a
protractor, or by using aspecially designed transparent plastic
board as is illustrated in Figure 3. The line EF,which is
perpendicular to the sides AB and CD of the rectangle ABCD, plays
the role ofthe reference line of a wale in the ideal perpendicular
relation that exists between walesand courses in an undistorted
knitted fabric. If the line AB tallies with a course and theline EG
lies along the actual line of the wales, then the angle FEG is the
angle of spiral-ity. Using the distances AD10 cm and FG (h cm),
Oinuma and Takeda (1988) calcu-lated the percentage spirality (PS%)
which is expressed by the following equation:PS(%)(h/10)100 and it
is considered as the sum of the net spirality caused by theyarn
torque and the additional spirality caused by all other
factors.
Figure 3: Transparent board with a protractor configuration
A E B
D F G C
8 E E E , Vol VIII, No 1, 2003
-
Another test method for measuring the spirality of the knitted
fabrics has been pro-posed by AATCC [Bailey, 1992]. In this test,
the fabric samples are marked with a squarebefore washing and
drying (Figure 4) and the change in the diagonals of the square
ismeasured to calculate the percentage spirality (PS) given by the
following formula:
PS(%) 2
(
(
A
B
C
D
B
A
D
C
)
) 100
Nutting (1960) has stated that for a full quantitative
description of spirality, both di-rection and angle must be
quoted.
Figure 4: Method for the calculation of the percentage spirality
(by AATCC)
4. Acceptable spirality
Over many years in dealing with spirality, many workers,
researchers and manufac-turers have set limits of spirality
acceptability. For some, the maximum spirality angle of5 is
acceptable [Nutting, 1971, Smirfitt, 1975] whereas for Haigh (1987)
the angle of 7is taken as the upper limit. In United States [West
Point Stevens, 1993] a percentage spi-rality of 8% is considered as
the maximum a fabric may exhibit to be acceptable by themaking-up
industry.
5. Distinction between spirality and drop effects
Bailey (1992) has described the spirality or wale skew as the
resulting configurationof a knitted fabric where the wales are
skewed from the vertical. The reason for this dis-tortion is the
yarn twist liveliness. On the other hand, if the courses skew from
the hori-zontal, the apparent effect of the fabric is called course
skew (Figure 5). This has alsobeen termed by Oinuma & Takeda
(1988) as the drop or corkscrew effect and is in-herent in the
process. This occurs due to the helical disposition of the courses
[Anon.,1980] and depends on the fact that articles produced with a
spiral configuration have astart and an end of a coil not on the
same plane.
The spiral distortion of single jersey tubular knitted fabrics.
I. Description... 9
-
Figure 5: Comparison between Drop and Spirality effects
In weft circular knitting machines, fabrics present a course
skew because the yarn isknitted in the circumferential direction
[Buhler & Haussler, 1985]. According to Brack-enbury (1992),
the degree of the course skew or drop depends on the number of
feedersused on the knitting machine. In recent years, the machine
manufacturers tend to increasethe number of feeders. For this
reason, the problem is likely to become more acute. Thedegree of
drop is a function of the step S of the helix (Figure 6) due to the
number ofcourses knitted per revolution of the machine, to the
number of courses per centimetre[Anon., 1980] and the machine
circumference. The direction of the inclination of the dropdepends
on the direction of either the revolving cam box or the rotating
cylinder.
C C
W W
Z S
Drop (Course Skew)
W W
C C
Z S
Spirality (Wale Skew)
10 E E E , Vol VIII, No 1, 2003
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Buhler & Haussler (1981) and Araujo & Smith (1989)
suggest that both the spiralityand the drop effect contribute to
the final distortion or total spirality of the fabric. It be-comes
essential therefore, to describe the effect of the number of
feeders on the drop phe-nomenon as well as to investigate the
contribution of the drop to the total spirality ofthe produced
fabrics.
Figure 6: Effect of the number of feeders on the fabric drop
(course skew)
D
Arrangement of a Course in aKnitted Fabric (One Feeder)
DOK
Opened Form of the Figure
LS s
(a)
D
Arrangement of a Course in aKnitted Fabric (Four Feeders)
DOK
1
Opened Form of the Figure
M
S1
(b)
The spiral distortion of single jersey tubular knitted fabrics.
I. Description... 11
-
5.1. Drop effect
In order to investigate the influence of the number of feeders
on the drop effect, themodel illustrated in Figure 6 has been
used.
Assumptions:
The height of a course (stitch - loop row) or the distance
between the central lines oftwo adjacent courses (step S of the
helix) is one millimetre. In the Figure 6a one feeder isused while
in the Figure 6b, four feeders are used. The diameter of the
tubular fabric isassumed to be 23 cm. The various curved (spiral)
lines represent a possible ideal positionof the central lines of
the successive courses.
Opening the fabric (cutting along a wale) it can be seen that
the length of a coursein the first case (Figure 6a- one feeder) is
smaller than that of the other case (Figure 6b-four feeders).
Following simple geometrical analysis it can be seen that:
OL ((23 )2 1) OL 72.2567 cm
Also, OM ((23 )2 42) OM 72.2577 cmThe difference 0.001 cm of the
length of the courses due to the insertion of three more
feeders can be neglected since the nominal width OK of the
opened fabric is 72.2566 cm(d 23 cm).
Furthermore, the inclination of the course in the fabric can be:
for one feeder 0.00138 % or 0.0793 (tan-1(S/OK)) for four feeders
0.00152 % or 0.317 for 144 feeders 0.14375 % or 3.038
Note: Machines with 144 feeders usually have a diameter of 86.36
cm (34 inches). There-fore the length of a course will be ((86.36
)2 1442) 271.69 cm.The width of the opened fabric is 86.36271.3 cm
and the angle will betan-1 (14.4/271.3) 0.053 rad or 3.038.
The angle of inclination in all the cases is negligible,
although the insertion of three ex-tra feeders, in the second case,
increases the angle by 75 % (angle ).
In the extreme case of machines with 160 feeders, the
inclination in terms of angle de-grees could be considered as
contributing to the total spirality, leading to a first con-clusion
that a large number of feeders alters, although slightly, the
spirality.
Araujo and Smith (1989) attempted to explain their statement of
total spirality bycarrying out the following analysis:
Figure 7 represents the development of spirality in a single
jersey fabric knitted witha Z-twisted yarn on a multifeed circular
machine with an anticlockwise rotating cylinder.
12 E E E , Vol VIII, No 1, 2003
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Figure 7: Spirality of a single jersey fabric knitted from a
Z-twisted yarn on a multifeedcircular machine with an
Anticlockwise-rotating cylinder.
XX Position of a course due to the total spirality = N/W (open
width of fabric);AA Position of a wale due to the total
spirality;BB Position of a wale when spirality (drop) due to the
number of feeders exists;XD Position of a course when spirality
(drop) due to the number of feeders exists;XD Displacement between
two consecutive courses knitted by the same feederF/C;F Total
number of feeders on the knitting machine;N Total number of needles
in the knitting machine;C Number of courses per unit length;W
Number of wales per unit length;f Spirality (drop) angle due to the
number of feeders (YO
^B);y Spirality angle due to the yarn twist liveliness (BO
^A); fy Total spirality angle (YO
^A or AO^Y).
From the triangle DXX:
tanaf N
F
/
/
W
C
N
F
W
C (1)
Considering that W K
W , C
K
C (2)
and loop shape factor KC/W K
K
W
C (3)
where KW, KC are non dimensional parameters whose values depend
on the state of re-laxation and is the loop (stitch) length (mm),
then,
tanaf KC
1
/W af tan
-1 N
F
KC/W (4)
FN
ABY
D
X
YB
X
A
af
af
afy
ay
The spiral distortion of single jersey tubular knitted fabrics.
I. Description... 13
-
From the last equation it could be stated that the angle of the
course skew (drop) de-pends not only on the number of feeders but
also on the shape of the loop in the particu-lar state of
relaxation and on the number of the active needles in the knitting
machine,which in turn depends on the machine cut and diameter.
If the direction of the rotating cylinder reverses (i.e.,
clockwise) then Figure 7 will changeto the form shown in Figure 8,
indicating that the overall spirality angle will be reduced.
Figure 8: Spirality of a single jersey fabric knitted from a
Z-twisted yarn on a multifeedcircular machine with a
Clockwise-rotating cylinder.
It could be concluded then that, in many cases it would be
beneficial rather than detri-mental, from the total spirality point
of view, to use a large number of feeders on a ma-chine, as the
drop (due to the number of feeders) and the spirality (due to the
yarn twistliveliness) can combine together to create more skew, or
they may partially offset eachother and result in less skew
[Bailey, 1992]. On the other hand, multiple feeders increasethe
chance of a stripy fabric being produced because of possible yarn
linear density and/orshade variation between feeders [Walker &
Sleath, 1950].
Further to the conclusions of the above investigation, it has
been suggested [Anon.,1958] that the number of feeders is
responsible only for a distorted appearance of the fab-ric (in
terms of drop effect), while the actual spirality is the same
whether a single or mul-tifeed machine is used (Figure 9).
Figure 9: Appearance of a distorted fabric due to the drop
effect (a. one feeder - b. five feeders), with 0 Spirality
Angle
a b
AB Y
D
X
Y B
X
A
af
af
afy
ay
14 E E E , Vol VIII, No 1, 2003
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References
Anon., (1958). More about spirality, Knit Knacks, Vol. 3, No 3,
p. 10Anon. (1980). Complement aux etudes de vrillage des tricots,
ITF Maille Bull. Scient.,
Vol. 9, No 33, p. 85Araujo, M.D. and Smith, G.W. (1989).
Spirality of knitted fabrics. Part I: The nature of
spirality, Textile Research Journal, Vol. 59, No 5, p.
247Bailey, D.L., (1992). Factors affecting the skew of 100% cotton
single jersey fabrics, Air
Jet Spinning Conference, College of Textiles, NCSU, Charlotte,
N.C., May 28Brackenbury, T., (1992). Knitting Clothing Technology,
Blackwell Scientific Pub., Ox-
fordBuhler, G., Haussler, W. (1981). Skewed stitches in plain
jersey fabrics, Textil Praxis In-
ternational, Vol. 36, No 10, p. 1092Buhler, G., Haussler, W.
(1985) Influences affecting the skew of single jersey fabrics,
Knitting Technique, Vol. 7, No 6, p. 373Charnock, I.L.A. (1977).
Yarn quality for knitting, Textile Institute & Industry, Vol.
15,
No 5, p. 175 Davis, W., Edwards, C.H., Stanbury, G.R. (1934).
Spirality in knitted fabrics, Journal of
the Textile Institute, Vol. 25, No 3, p. T122Davis, W., Edwards,
C.H. (1935). Spirality in knitted fabrics: II Cotton, Journal of
the
Textile Institute, Vol. 26, No 3, p. T103Dutton, W.A. (1951).
Faults in knitting yarns, Hosiery Times, Vol. 24, No 270, p.
54Fletcher, H.M. & Roberts, S.H. (1953). Distortion in knit
fabrics and Its relation to
shrinkage in laundering, Textile Research Journal, Vol. 23, No
1, p. 37Haigh, J.S. (1987). Loop distortion in plain knit fabrics,
Wool Science Review, No 64,
p. 81.Hughes, J.W. (1945). Distorted loops (Avoided by knitting
machine adjustment), Tex-
tile World, Vol. 95, No 12, p. 123 Leaf, G.A.V., Glaskin, A.
(1955). The geometry of a plain knitted loop, Journal of the
Textile Institute, Vol. 46, No 9, p. T587Munden, D.L. (1959).
The geometry and dimensional properties of plain-knit fabrics,
Journal of the Textile Institute, Vol. 50, No 7, p. T448Nutting,
T.S. (1960). Spirality in weft knitted fabrics, HATRA Research
Bulletin, Vol.
4, No 6, p. 18
The spiral distortion of single jersey tubular knitted fabrics.
I. Description... 15
-
Nutting, T.S. (1971). Spirality in weft knitted fabrics, HATRA
Notes, No13Oinuma, R., Takeda, H. (1988). Spirality in plain-jersey
fabrics knitted of three-ply cot-
ton yarns, Journal of Textile Machinery Society of Japan
(English edition), Vol.34, No 3, p. 74
Parker, R. (1981). Cockling in fully-fashioned garments,
Knitting Industry TechnicalReview, Vol. 1, No 2, p. 25
Roytowski, R. (1972). The effects of spinning variables on
deformations in plain knittedfabrics, M.Phil. Thesis, The
University of Leeds, Leeds, England
Smirfitt, J.A., (1975). An introduction to weft knitting,
Merrow, WatfordStacey, P. (1957). Twist Liveliness, HATRA Research
Bulletin, Vol. 4, No 1, p. 17Stevens, J.C. (1985). Knitting to
specification, African Textiles, Dec./Jan., p. 28 Textile
Institute, (1995). Textile Terms and Definitions, 10th Edition,
Textile Institute,
ManchesterWalker, E.M., Sleath, C.E., (1950). Defects in knitted
structures due to yarn irregulari-
ties, Journal of the Textile Institute, Vol. 41, No 7, p.
P559West Point Stevens, N.C., U.S.A., (1993). Private
communication
16 E E E , Vol VIII, No 1, 2003
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E-learning in Greece:The right content for the right purpose
Fedon KomissopoulosTechnology and Operations
ManagementUniversity of Piraeus
George GagalisComputer EngineeringMathematic University Messina
Italy
Abstract
The distance learning using electronic means and a whole
philosophy is concentratedin the world "e-Learning". This paper has
a goal, to give a first clear view of e-Learningunder the prospect
of content that is going to be distributed over a certain
technology in-frastructure, having clear objectives (education,
training) so that results are visible andmeasurable. Further, there
is an analysis of the participants in the Greek eLearning mar-ket
(the Greek value chain with the key players) to shade light on some
times similar andhazy meanings and the future trends of the market.
This paper is the outcome of data col-lected from interviews with
managing staff of the e-Learning markets companies.
fi "e-Learning". fi fi e-Learning fi fi , fi (-, ) . -,
e-Learning -fi fi , . - fi e-Learning .
E-learning in Greece: The right content for the right purpose
17
Vol. VIII, No 1, 2003, pp. 17-34
-
1. Introduction
The last few years, many companies have joined the competition
field of distancelearning using new technologies, especially with
the use of Internet.
Like everything, this business effort should have a specific
goal and philosophy. Com-mon questions like for whom do I provide
my services, using what and how should I pro-vide it, need answers
in order to have a prosperous business horizon.
That is why, after a thorough study of the Greek relevant market
place, we presentconclusions that will reveal to us that even if we
are dealing with new technologies, moretraditional principals still
affect the quality of our service.
Principals like What is the really need of my customer? Get
trained or tought?Then the implementation of the offered solution
to a specific and well-positioned re-
quest has better results.
2. What is e-Learning?
E-Learning refers to anything delivered, enabled, or mediated by
electronic technolo-gy for the explicit purpose of learning
(American Society for Training and Development).
Of course there are so many other definitions that a book could
not include all of them.For our purposes we would agree with the
glossary of elearners.com
(http://elearners.com/services/faq/glossary.htm) on any
definition.
E-Learning tends to be considered as a tool for knowledge
management, performancesupport and virtual communities for many
organizations, a strategic tool something thatis not happening with
e-Training (www.astd.org).
3. How did e-Learning occured?
Figure 1
E-BusinessDistance
LearningE-Learning
18 E E E , Vol VIII, No 1, 2003
-
It is very clear to see that e-Learning seems to be an
e-business aspect that joint thephilosophy and flexibility of
distance Learning with the revolution of telecom, network-ing and
new media.
4. Other subclasses
Figure 2
If one would take the distance Learning point of view, we see
that e-Learning is some-thing quite smaller from distance Learning
philosophy and practice, just because of theuse of new technology,
which goes from total e-Learning (satellite, LAN, Wan and
inter-net) to a simple Computer Based Training.
Although right now we present subclasses based upon technology,
soon we will come tothe conclusion that the content and the need
are what make the final separation of definitions.
5. How is e-Learning delivered?
A wide range of technological options is available to the
distance educator: Voice (audio conferencing, tapes, voice mails )
Video (slides, film, videotape and real-time moving images combined
with audio con-
ferencing - Videoconferencing - instructional TV) Data
(electronic mail, fax, real-time computer conferencing, and
World-Wide Web
applications, Computer-assisted instruction (CAI) uses the
computer as a self-con-tained teaching machine to present
individual lessons, Computer-managed in-struction (CMI) uses the
computer to organize instruction and track student recordsand
progress. The instruction itself need not be delivered via a
computer, although
Distance
LearningE-Learning
On Line
LearningCRT
E-learning in Greece: The right content for the right purpose
19
-
CAI is often combined with CMI. Computer-mediated education
(CME) describescomputer applications that facilitate the delivery
of instruction.
Other off-line products: DVD, CD-Roms etc. Print is a
foundational element of distance education programs. Various print
for-
mats are available like textbooks, study guides etc.Going a bit
more further on the technology side of e-Learning we can see two
types
of learning:
5.1. Synchronous - Asynchronous Learning
Synchronous learning, during which trainer (educator) and the
trainees (students)have to be at the same time in front of their
PCs (or videoconferencing systems, inter-active TV, or desktop
video conference) in order to communicate and create that
specialeducator - student relationship. That means that using this
method we can have 100% online lesson, live questions, better
relations between students etc.
Asynchronous learning is the opposite thing. The session is
recorded and it is avail-able on demand on the server, or it is
sent attached to e-mail and send to the target group.That means
that the student can read the teachers mail at night, do his/her
homework dur-ing office hours and join a forum at dinnertime.
The most common method of learning is a mix of the above. That
is because all stu-dents must have "physical" date with other
fellow students in order to gain team spirit andcommon sense of
what they are doing and the fact that they have different paces-
theymight even be at different time zones. Of course there are
economic reasons also, like thecost of a full videoconference
program, or video on demand. Finally, the mix of synchro-nous and
asynchronous training gives the rate of self-paced programs.
5.2. Advantages of e-Learning
E-Learning has advantages for both for the trainer and the
trainees. Let us not forgetthat it was planned to be for people who
are geographically far away from school or uni-versity campuses
The above also includes people who do not have time to go to
university, or oppor-tunity, even if they live next to it, ex they
are working many hours, or they are disabled.
The total educational content is easily modified and maintained,
always updated, nomore wasted time neither going to campus, nor
renting a house near the campus.
Here is a short list of the advantages of e/l: Reach a wider
student audience Broad array of choices: earn a degree, sharpen
your work skills, obtain continuous ed-
ucation credits and prepare for a new job, all without leaving
the keyboard.
20 E E E , Vol VIII, No 1, 2003
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Meet the needs of students who are unable to attend on-campus
classes Involve outside speakers who would otherwise be unavailable
Link students from different social, cultural, economic, and
experiential backgrounds Usually e-Learning programs are self paced
Usably e-Learning programs are finished in shorter time than
traditional programs.
5.3. Disadvantages of e-Learning
Of course there are some disadvantages, like: Participants do
not develop their communication skills (compared to traditional
ways), In order to get in the e-classroom you will need fast and
expensive equipment (hard-
ware and software speaking) Lets not forget that web is not
always up and running. The platform and the content of e-Learning
need very responsible designing. It has
happened before, while IT leading companies were creating
educational software with-out even asking psychologists or
teachers.
Someone has to ready to invest sufficient time for his program.
E-Learning programs are some time two times more expensive than
traditional ones. One must be quite disclipine, with critical
thinking Good knowledge of access equipment (modem, email, web
browsers etc.)
5.4. Other e-Learning issues:
5.4.1. E-Learning and Copyright
A copyright grants the holder the sole right to reproduce or
grant permission to oth-ers to reproduce the copyrighted works. The
copyright holder is defined as the person whoowns the exclusive
rights to a work. The protection is limited to original works,
whetheror not they have been published. However, it is the
expression of the idea that is copy-righted, not the idea in and of
itself (Brinson and Radcliffe, 1994).
Educators have always utilised outside resources to enhance the
Learning (and e-Training) experience for their students. These
resources can range from a newspaper clip-ping to a book to a
movie. All of these items, and many other resources, are
copyrightedmaterials. There are both civil and criminal penalties
for infringement of copyright law.
Distance educators have a unique dilemma when dealing with
copyright law. Due tothe time that the law was passed and the rapid
advancement of technology for distance ed-ucation, the provisions
for education in the copyright law are often unclear for the
dis-tance education classroom. It is very good for us to know that
the same content in a tra-ditional program of a university is also
copyrighted and used on-line.
E-learning in Greece: The right content for the right purpose
21
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5.4.2. What is ROI?
When you are planning to do business, the main thing you want to
know is what willyou gain for every money unit you will invest on
your new business. That is an easy wayto understand when you begin
to make profit. We call that Return On Investment.
It is very good to see education that way, especially when you
are paying to educateyour employees. How many seminars and work
hours have been wasted? What did youget back as performance of you
staff who got that extra training?
In order to calculate ROI you will need to be able to measure
the total financial ben-efits derived from a program and then
compare it to its costs.
For example, if someone is translator and took a program where
would be taught howto use MS Word more efficiently, and the total
outcome of our written translations wouldincrease, so would his/her
income!
The only thing we have to do is to translate it to numbers: ex.
Before we could type 5translated pages per day, after the seminar
we can type 15 and give it to the customerfaster, so 10 pages * our
price/page is our total benefit from the seminar.
And ROI is {(Total benefit - Total cost)/Total cost} *100. Keep
in mind that ROI can-not take all benefits into account. It is only
a number. But what that has to do with e-Learning?
The reduction of traditional training programs of course. Well,
first of all, the multime-dia approach saves time! (35-45% training
time reduction) That is the first cost we can cut-back! The second
cost is the cost of travel and take your car to go to the seminars.
An oth-er cost you can cut is that of people missing from work in
order to attend to the seminar.
5.4.3. Is e-Learning (and e-Training) effective?
Effective distance education programs begin with careful
planning and a focused un-derstanding of course requirements and
student needs. Research suggests distant studentsbring basic
characteristics to their learning experience, which influences
their success incoursework. Distance education students are
voluntarily seeking further education. Most-ly, they have
post-secondary education goals with expectations for higher grades,
they arehighly motivated and self-disciplined and they are
older.
5.4.4. How Important is Interaction?
Research findings on the need for interaction have produced some
important guide-lines for instructors organising courses for
distant students, for example: Learners valuetimely feedback
regarding course assignments, exams, and projects, learners benefit
sig-nificantly from their involvement in small learning groups.
These groups provide supportand encouragement along with extra
feedback. Most importantly, the groups foster thefeeling that if
help is needed it is r available; Learners are more motivated if
they are in
22 E E E , Vol VIII, No 1, 2003
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frequent contact with the instructor. More structured contact
might be utilized as a moti-vational tool. (Thrilled &
Bronska,1994)
5.4.5. How does e-Learning work?
E-Learning and costPer course or per credit as well as any
additional charges must be clear to you before
deciding. Also payment methods are a bit more "e" ex. Major
credit cards. Do not forgetthe cost of dialing in from your PC in
order to participate in the course.
What is the best Technology mix in order to provide an
e-Learning program?Using this integrated approach, the educator's
task is to carefully select among the
technological options. The goal is to build a mix of
instructional media, meeting the needsof the learner in a manner
that is instructionally effective and economically prudent.
5.4.6. Evaluating students
When teaching at a distance, educators must address a different
teaching challengethan when teaching in a traditional classroom.
For example, instructors no longer have Atraditional, familiar
classroom, A relatively homogeneous group of students,
Face-to-facefeedback during class (e.g. students' questions,
comments, body language, and facial ex-pressions), Total control
over the distance delivery system, Convenient opportunities totalk
to students individually.
For these reasons, distance educators may find it useful to not
only formally evaluatestudents through testing and homework, but to
use a more informal approach (see Ange-lo and Cross, 1993) in
collecting data to determine:
"Student comfort with the method used to deliver the distant
instruction, Appropri-ateness of assignments, Clarity of course
content, If class time is well spent, Teaching ef-fectiveness, How
a course can be improved."
5.4.7. Types of Evaluation
Evaluation can be either formative, summative, or a combination
of both.Formative evaluation: Is an on-going process to be
considered at all stages of in-
struction Will enable the instructor to improve the course as
he/she proceeds, Facilitatescourse and content adaptation. Will
identify major gaps in the instructional plan or theneed for minor
adjustments. Some strategies that educators can use to collect
formativedata from their distant students such as electronic mail,
postcards etc calls at other times.
Summative evaluation: Assesses overall effectiveness of the
finished product orcourse. Can be a springboard in developing a
revision plan. Can be a baseline of infor-mation for designing a
new plan, program, or course. Will not help current students
sinceit is conducted upon course completion. Some questions that
educators may want to ask
E-learning in Greece: The right content for the right purpose
23
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students when collecting summative data include: weaknesses of
the course or strengthsof the course, If you were teaching the
course, what would you do differently, and so on.(Angello &
Cropps , 1993)
5.4.8. Evaluation Methods
Within the context of formative and summative evaluation, data
gathered throughquantitative and qualitative methods.
Quantitative evaluation: Involves asking questions, which can be
statistically tabu-lated and analysed, frequently using a scale,
check list, or yes/no responses. Limits stu-dents to responding to
the categories made available to them. Needs a large student
sam-ple for relevant statistical analyses. (Angelo & Crops,
1993)
Qualitative evaluation: Is typically more subjective. Involves
gathering a widerrange and depth of information. Is more difficult
to tabulate into neat categories. Will beless affected by typical
small class size. Is a more flexible and dynamic method? Is not
lim-ited to pre-conceived topic of inquiry. Allows for student
output of topics. (Angelo &Crops, 1993)
Although the above aspects of e-Learning (and e-Training) are
critical, there is onehidden aspect that has much to do with
technology. It is the content.
6. The content
Definitions: Content: Defined through its function and context
information, transaction, enter-
tainment, education and lifelong learning E-Content: information
published on any internet platform, from the web to wireless
devices, to internet appliances and broadband television
(From the e-content meeting held in National Documentation
Center in Athens, 23rdof November 2001 with mss Heli Lehtimaeki,
commissioner of European Committee forSociety of Information)
Technologically speaking, the content of an e-Learning procedure
comes from thecombination of traditional media and new media. From
a quality point of view, eventhough technology can present an
appropriate content the right way, it is very commonto present the
inappropriate content the wrong way, just because we had not set a
spe-cific quality goal, or we did know the exact use of the
content.
Let us take for example that we have a need and we address to a
company. The firststep is to sit down together with the customer
and discuss the need, for example the needfor his secretary to
learn and use commercial correspondence in French language.
24 E E E , Vol VIII, No 1, 2003
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The second step is to define the level of knowledge we want the
knowledge target (thesecretary) to acquire- and what is the present
level of knowledge.
The third step is to set the time frame we want to achieve that
(it may be a week or 6months).
After those three steps we are ready to plan and create or adapt
an existing programto our customers needs. See again, we are very
much interested in time and level ofknowledge.
Figure 3
Figure 4
Step 1 Step 2 Step 3
Step 1 Step 2
Linear Content narration - Presentation
Non-linear Content narration - Presentation
Step 3
Step 4 Step 5 Step 6
Linear
ComplexLengthy
ConciseBrief
UserContact
Time
Narrative non-Linear
Teaching Education
Training Reference
browsing
E-learning in Greece: The right content for the right purpose
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On the scheme above we can see the relation between time and
content complexitybut one must have a very clear view of what is
the desired outcome of the content pro-duced. (Yale University)
According to the Oxford Reference section dictionary, to "Train"
someone is to bringhim to a desired standard of performance by
instruction and practice, especially for an oc-cupation. According
to the Yale scheme, when training someone, the content should
bebrief and very linear (from step 1 to step 2 and step 3-end).
In the same dictionary we can find also:"Reference": referring
to a source for information (very brief content but in no case
lin-
ear)"Teaching": to impart information or skill to a person or
about a subject, systematical-
ly. As expected, the content used for this scope should be
linear (systemat-ically) but lengthy enough to cover all aspects
(theory and practice). Teach-ing is the most used method for
Learning, so we tend to use the word learn-ing (and e-Learning)
although the word teaching is more precise.
"Education": refers to systematic instruction with aspects of
character development. Thelengthiest and most non-linear of
all.
"Browsing": is to read or inspect items on display covers a
small part of everything.
So, from now on, even if we use the term learning (knowledge
acquired by study) wemean something deeper that has to do with the
complexity of the offered content and thedesired outcome of the
procedure.
For our example with the secretary, some short courses -
seminars on commercial cor-respondence (TRAINING) would do just
fine.
An other issue one should consider that the content (at least
the biggest part of it) inall "e" activities consist of multimedia
and that is why e-Learning has so many tools topass the right
meaning over its audience.
Something to keep in our minds: In the traditional educational
process, content weremost of the times in text format. In
e-Learning, e-Training etc, content is a combinationof text, sound,
video, images, animation, simulations etc.
Distributing content for e-Learning purposes can be something
just in time and quitepersonalized thanks to content management
platforms.(e-week, 15th Nov.01)
Closing this section, we draw, as conclusions that content can
not be stable. It must beadjusted to specific needs the learner
has.
So, right now I believe we can make a first separation of
meanings depending on tech-nology used and desired outcome. This
summative table is a first impression from the in-terviews and the
bibliography studied.
26 E E E , Vol VIII, No 1, 2003
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Infrastructure Most common way From the content point of
view
(distribution channel of communication
/path for delivering (Synchronous Learning Training
Education
content) -asynchronous)
Using all types
of infrastructure
(Satelite, Internet,Synchronous e-Learning e-training *
Intranet, Lan, PC)
Using almost 100%Synchronous
On line Learning On line On line
Internet (and e-Training) training education
Using LAN, WAN
& Intranet - Internet AsynchronousWeb based Web based
*
- Extranetlearning training
Using off-line products **Computer
(CD-Rom etc)Asynchronous *
Based Training*
* No standard reference was found in any interview or in the
studied bibliography** If you have children it is most likely that
you have gone home with a CD-ROM for example "
my first chemistry lessons" just to help them with their
chemistry at school. That was their firstcontact with CBT.
7. Impact of e-Learning (and e-Training) in the labor marketin
the future
There will be demand for roles of the following three kinds of
people, because of e-Learning:1) Animation/Multimedia developers:
these will be the people who actually code and
program the e-Learning modules2) Learning consultants: people
with functional experience of the training and develop-
ment industry who will act as functional consultants when a
Learning Managementsystem (ex. SABA) is to be deployed in an
existing training establishment
3) Content Developers: These will be people who will ultimately
convert the offline con-tent to content suitable for e-Learning and
will be instructional System Designers.
Some of them already exist or they play more than one role (ex
content developer andmultimedia developer), but there will be an
increase of demand for staff with such knowl-edge with expertise.
(From e-Learning: Rhetoric vs Reality, Gautam Ghosh,
www.hu-manlinks.com/manners/articles/e_learning .htm,
16/10/2001)
E-learning in Greece: The right content for the right purpose
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8. What is the total learning solution?
It is the mix of Technology Content Services Personnel to assist
the aboveoffered by a provider that can meet the need of his client
for distance education using
new technologies.
In order to have a more helicopter view of the situation in
Greece, most important is-sues and findings from the interviews
will be presented in the following pages.
9. The business model
9.1. Present situation in Greece
Although it is true that Greece is a slow starter, when talking
about new technologiesand new habits concerning technologies, we
have experienced great changes past fewyears.
Already 1 out of 2 persons has a mobile phone, 7 out of 10 have
a PC in their homeor office but only 1 out of 10 has an internet
connection. This very small percentage isnot caused only from the
still expensive cost of dial up or the charges of our local P.T.Tor
even the "untrustworthy" for many people Greek telecom
infrastructure.
While Europe is going mobile (From the e-content meeting held in
National Docu-mentation Center in Athens, 23rd of November 2001
with mss Heli Lehtimaeki, commis-sioner of European Committee for
Society of Information), Greece has a very good per-formance on
adapting e-Learning applications (according to CEDEFOP,
www.train-ingvillage.gr).The 43% of the Greek participants to the
survey of CEDEFOP answeredthat provide or use methods and tools for
e-Learning.
The problem is that there is no clear picture (not only for
Greece but for the entireEC) regarding cost and profit evolution.
(CEDEFOP)
9.2. A survey
When stuff, from the signor management of companies (most of
then managing di-rectors, marketing managers and new business
developers) whos main part of incomecomes from giving e-Learning
solutions, was interviewed, interesting things, that will
bepresented to you right away, were found.
28 E E E , Vol VIII, No 1, 2003
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In order to be able to make this specific interview, we designed
a questionnaire withopen-ended questions (Companies names and
personal data of participants available). Inmost situations the
interview was more an open dialogue with many findings that we
triedto include in these pages as clearly as possible.
First of all, e-Learning for most companies that give e-Learning
solutions, is just a ter-minology which describes transferring data
of any form (video, sound, images) transferredto the target by any
electronic mean (satellite, digital TV, internet, intranet,
CD-ROMetc.) for educational purpose.
No different definitions for describing e-Learning and
e-Training or e-education werereferred, but every one of the
interviewed people agreed to the Yale differentiation con-cerning
content and final result of the procedure.
9.3. The business model
Even further, all players behind the line, meaning those who
cooperate in order to givea total e-Learning solution to the
customers, have many beliefs in common. For example,it is very
clear for them that e-Learning (and e-Training) was the outcome of
distanceLearning (and e-Training) and e-business (as presented
before).
The model is divided in two parts: starting from the left, the
content developers the platform developers the distributors of the
service
The second part is the customers part: end customers (consumers)
educational institutions Corporate customers
The customers side will not be analyzed. The reason we did such
a separation was toshow the use from the customer. A corporate
customer is going to resell it or get moremoney from the skills he
took an end customer is taking and keeping the knowledge forhim
self etc. Further, there is a categorization based upon a marketing
approach that ismore complete.
ContentProviders(producersor resellers) A
Platformdevelopersor resellers) B
Distributorschannels(ISP' s etc.) C
EducationalInstitutions E
End customers D
Corporate F
E-learning in Greece: The right content for the right purpose
29
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The whole model is the value chain. The total value of this
chain is not easy to compute,because each part of the value chain
may be "asset" of each other. That is a very commontactic for big
companies that want to be established as total e-Learning solutions
providers.
Total e-Learning provider according to the interviewees, is the
company who haspresence to all the elements of the first part of
the model. Only 20% of the players are to-tal solution
providers.
10. The first part
A. Content developersContent developers and/or resellers.
Mainly, companies that have a traditional rela-
tionship with educational content. "It is easier and cheaper to
localize a content fromabroad than to create it" that may sound
logical, but that is exactly where Greek e-Learn-ing industry
starts to fail its own market. As many times before, even today we
try to lo-calize content rather than create something to respond
our own needs.
That is why most courses available on line are soft (business)
skills or IT skills devel-oped e.x. in Israel, localized for Greek
market.(communication solutions, p.48, 16th issue,Nov-Dec01)
Few exceptions try to take head of the market and as
interviewees said they have agood chance because the produce their
own content based on realistic needs. (Tailormade, as we will see
later on).
An other case that e-Learning is working subservient and not
competitively too tra-ditional learning is the following:
Private tutorial centers have placed their content on
asynchronous platforms and stu-dents who missed classes or want to
read more about a specific subject visit the virtualclassroom.
The content must be adjusted to the specific needs of the
customer, to the technolo-gies used, to the platform and of course
the courses objectives.
It is very difficult to give access to a dial up user in virtual
classrooms were on linelectures take place.
B. The platform developersActually, 50-70% of the involved
companies just buy platforms developed abroad and
pay for rights. The company with the platform is actually the
main player who tries to at-tract customers. From a quality point
of view it is not supposed to be that way because aplatform is the
outcome of technology, designed accordingly to meet some needs
andstandards.
The feeling we have from the interviews is that the content
developers should attractthe customer and the features of the
platform should just be added value services.
30 E E E , Vol VIII, No 1, 2003
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Platforms are mainly divided in satellite and Internet
platforms. Also, synchronousand asynchronous (according to the
synchronous or asynchronous way the are going tobe used). Even if
the trend is to use synchronous platforms, in everyday life we see
theopposite, the use of asynchronous platforms. And it is not the
cost of a synchronous les-son, or the telecom infrastructure that
has the last word for the choice between a syn-chronous and an
asynchronous platform. It is the use, what positives of e-Learning
(ande-Training) we intend to take advantage off.
The Greek value chain according to the interviewees has a very
big question markfor this part of the model. Mainly because other
financial factors reflect - react on them.For example, Piraeus bank
trying to be in every "e" business bought 41% of EXODUS.
The cost for a platform may vary and it depends of the users.
Most platforms are usedon a server and the server is connected to
the Internet or the Intranet of a company.
C. The distributorsFor e-Learning (e-Training etc) applications,
the classical distribution technologies
are: Satellite, TV, Internet, Intranet, videoconferencing. If we
were talking about on lineor wbt, a www location would do, provided
the hosting services by the ISP .
An Application Service Provider would have more things to give
to a total e-Learningsolution provider (cost savings on technical
support-personnel, value added services etc.).
11. The second part
Taking a marketing point of view, some target group and
potential customers can beunrelieved, and so proactively the
companies can adjust their content, platform and dis-tribution
accordingly to attract the desired target.
If you put the words "e-Learning (and e-Training)" in any Greek
search engine youwill find about 70 entries. Those 70 entries are
all universities, companies and organiza-tions with dynamic
presence in e-Learning (and e-Training).
The way e-Learning is treated today by Greek reality can be
easily seen if someonecategorizes the service by Business to
Business, Business to Consumer, Government toConsumer, Government
to Business, Business to Government.
Business to businessCompanies mostly, for whose e-Learning is
just an other service to attract other com-
panies-customers. Their main goal is to provide complete
solutions educating companiespeople (e-Learning, seminars,
educational software, training based on new technologies,Decision
support systems etc).
Their expectations: Having a customer to one of their products,
their main effort is tomake him loyal customer to all of their
products, so maximizing the profits per customer.
E-learning in Greece: The right content for the right purpose
31
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Business to consumerCompanies that approach and deliver
e-Learning as the best cost-benefit solution for
modern people with no time but many educational needs,
unemployed people who isseeking further skill improvement,
youngsters for an extra help with school lessons.
Their expectations: Most of these companies use e-Learning at
the same time with tra-ditional educational programs complementary
but are also trying to deliver it as standalone product.
Government to ConsumerUniversities and other public sector
organizations. Aristotle University of Thessaloni-
ki, University of Crete and Ioannina, Ministry of Labor.
Providing programs for unem-ployed people, postgraduate students.
There is no full program on line yet, just some les-sons or
programs that lead you to Diploma.
Their expectations: Right now most of them are financially
supported by the Euro-pean Union and from a small fee of the
participants. Their main goal is to be well estab-lished on their
own funds by the time European financing will be over.
Some universities e.g. University of Ioannina are trying to
support their on line pro-grams in a way that the whole system will
be a separated entity from the university its self.Let us suppose
that a whole new company easy to finance will be established and
su-pervised from the university, or the ministry just to provide
e-Learning services, content.
Government to businessFor further education of people with
educational background, like training teachers of
primary schools in new approaches of educational psychology
(SocraTES), or trainingbusiness staff when they are scattered in a
wide area (University of Macedonia Tilemath-os=learn from far).
Their expectation is quite similar with the Gov2C, but they keep
a more humanisticapproach, meaning that they will keep their
non-profit status.
Business to GovernmentOn line programs from companies targeting
public sectors needs, e.g. If secretaries
from Ministry of Labor were taking the on line Ms Office
Tutorial.
Figure 5
Gov2C21%
Gov2B10%
B2Gov10%
B2C34%
B2B25%
32 E E E , Vol VIII, No 1, 2003
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12. How much an e-Learning program costs?
Suggestively prices are: 100 euro/user/year, for the rights of
use over an asynchronous platform (using a Learn-
ing management System) and 50 euro/user/course (any kind of
courses) 1.700 euro/user, fee for rights for using a synchronous
platform, plus 50 euro/user/
year/course (any kind of courses).
13. Epilogue
Closing this part it would be good to pay attention to two major
issues pointed outfrom the interviews.
The first issue is the idea of the funs of new technology that
e-Learning has come toreplace traditional education methods and so
e-Training will replace traditional trainingmethods.
That is totally out of our philosophy. E-Learning has come to
work supplementarywith traditional education-training and teaching.
The point is to take advantage of the ad-vantages e-Learning
provides, such as 24h/day availability, no place restrictions or
geo-graphical etc, not to adopt 100% a new system.
The second one is the need for tailor made products. Just like
in the real world noclient has exactly the same needs with the next
customer, so it happens to the digitalworld, and most of all when
we are talking about learning and training. It is of no use tocount
success or failure stories of Greek market.
Perhaps you have noticed on figure 5 that 34% of total
e-Learning solution is B2C ori-ented and if you visit some of the
biggest companies site you will find ready e-Learningpackages, pay
and go. Actually the biggest part of this market is working on
retail.(e.mar-ket, issue 11,Oct 01, p.58)
Maybe this is the reason why from 2000 to 2001 a 25% of the
relative URLs has been"currently unavailable". The entire business
environment is very competitive, so gettinga customer and keeping
him is matter of satisfying his needs with a better way, a
morecomplete way. Taking a lesson on Ms visual C++ and hanging it
on your site for sale;seems that this way is not going to work.
E-learning in Greece: The right content for the right purpose
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References
Books and e-Books:The Yale styles Interface Design:
(http://info.med.yale.edu/caim/manual/interface.htm)E-Learning:
Strategies for delivering knowledge in the digital age. Marc
Rosenberg, Mc
Graw Hill Editions, 26/10/2000.National Actions to Implement
Lifelong Learning in Europe, European Commission,
Survey 3, Cedefop-Eyrydice, 2001.Training and Learning for
Competence, Executive summary on the second report on
vocational training research in Europe, CEDEFOP 2001.Labour
Market & Skill Trends OAED publications, Athens 1999.Training
and Labour Market Institute of Technological Education, Athens
1996.EOMMEX, Facts and Dynamics, Eommex Publications, Athens
2000.
Papers presented in conferences:The e-content meeting held in
National Documentation Center in Athens, 23rd of
November 2001 with mss Heli Lehtimaeki, Commissioner of
EuropeanCommittee for society of Information.
E-Train conference for small and medium enterprises, held in
Patra 27/3/2002, with thesupport of GRNet.
Open and Distance Learning Education, June 2001 in the Greek
Open University inPatras, M. Meimaris, T. Zerva.
34 E E E , Vol VIII, No 1, 2003
-
: - 1990-2000
fi ...
fi -: fi. fi - fi . fi , , fi fi . fi . fi - ( , - , ) fi , fi.
, , . fi fi - fi ( - fi fi fi fi). - fi fi .
Abstract
Traditionally, migration in Greece was characterized as being of
one direction: out-going. Just recently this phenomenon inversed
and a large number of foreigners startedentering our country,
having as a result the modernization of the legal framework
con-cerning the emigrants. The consequences of the extended arrival
of migrants are of mul-ti-dimensional character. Apart from the
oversupply of cheep labour force (resulting thewage squeeze, the
propitious ground for investment, and the coverage of seasonal
needsetc.), the most important is that the labour force, which is
being used, is for the state poli-
: 1990-2000 35
Vol. VIII, No 1, 2003, pp. 35-49
-
cies point of view costless. The migrants aggravate their
counties with nutrition, educa-tion and health expenditures, while
the minimum benefit in the economy of their homecountry is the
remittances. Consequently Greek economic growth occurred due to the
ex-propriation of the incoming labour force.
1.
, fi fi fi fi , fi : . fi ( ) . , fi .
fi fi (19 ) , - . : 1890 1910 fi 400 ( fi 1907 2,7 ), 1951-71 ""
-1 700 (fi 1961 8,4 . )
. 1971-74 fi fi 150
fi . 1973 -
fi fi fi. fi fi -
, . fi , fi fi fi (backwash effect).
fi fi - (fi ) fi (- ). fi .
, fi (1974-2000), , fi fi fi .
, 1985 1989, - fi
36 E E E , Vol VIII, No 1, 2003
-
2.
1950 , fi fi fi .
fi fi fi , - . fi fi fi ... fi . , - fi , , fi fi fi .2
fi , fi (demonstration effect) - fi, .
fi (1973-) . (1973, 1979) , fi fi - . -, fi . fi ( fi " fi" fi
-) fi "" fi- fi.
fi fi - . fi fi, , fi , - -. fi - , fi , fi - , fi . -fi fi 2,9%
1969, 19% 1985 30% 1992.
: 1990-2000 37
-
3. fi
, fi , - fi , .
.4310/29 ( -, , ) fi- fi , -.
.5288/31 ( ) fi . .5405/32 .4310/29 - . fi fi 320/36 ( ) fi
.
.. 4429/64 , fi 448/68 . fi 1346/83 - fi .5405/32.
fi fi fi - . fi , fi fi- (, , , ).3
fi fi 1975/91 (fi - , , , - ) fi (4310/29).
fi . - 1991, 1992 ( fi -) fi fi ( ) fi fi ( fi fi ). fi fi "" fi
( fi 1999-2001 fifi ).
fi , fi fi. fi , fi .
38 E E E , Vol VIII, No 1, 2003
-
4. fi fi
fi .
fi fi , , ... - .
fi fi, , fi -. .. - .
fi , , fi , fi. - fi , fi , . ( -) fi fi .
, 1950, . fi fi fi , - , .
fi, fi: fi fi
. fi , -fi fi 40% - .4
fi. - fi .5
fi fi fi, fi fi . - .
fi ( 3%), . fi fi fi .
6 fi , ( ) fi ().
: 1990-2000 39
-
- , fi " " , , fi ( - fi fi), (). - , - , - . fi fi fi .
fi . fi -. 1970 fi fi 31,4% 1980 32,4% 1990 30,2%. . , fi, -, fi
... fi .
fi fi fi fi fi , , . - fi, fi fi, fi fi ( - ...), fi -, fi , "
".
fi (, , -) fi fi .
, fi -, ... fi fi fi fi . fi fi - , fi , fi , ( fi fi, .. fi
).
fi:i. fi : fi -
, fi , fi (, , , -, ...). fi, - fi .
ii. fi fi -
40 E E E , Vol VIII, No 1, 2003
-
fi . , -. fi , , fi - fi - . fi : fi (fi fi -
, ...) - ,
fi fi , ( fi ...).
fi fi fi ( -) fi fi .
fi .. (), , , , -, fi fi - fi.
fi "fi" ( fi -), fi fi -, fi , , fi - , fi - , fi fi fi .
fi fi fi .
fi fi . - fi fi , - , ( ), fi , fi, - , fi , -. "" , - , . -
1994 .
: 1990-2000 41
-
5. :
5.1. (1951-1971)
fi "- ". fi - (Lewis, Jorgenson, Todaro ) -. fi Kindleberger7 fi
fi fi fi -fi .
, , - fi , fi ( fi ).
, fi 1960, fi, fi ( ) .
fi fi 15-44 . ( 25-29, 20-25 ).
fi fi . - , ( fi fi), fi fi - .
fi , fi fi , , fi - .
fi fi fi -fi fi. ' fi " " . , fi fi fi - .
fi A. Sauvy8 fi fi fi 18 - (9) fi, fi (6) fi . Sauvy fi 9 , fi
.
42 E E E , Vol VIII, No 1, 2003
-
1 fi 10 .11
: 1990-2000 43
1
(
fi
fi
)
:
(199
5)
fi
fi
fi
fi
fi
fi
-
18
19
-59
fi
fi
fi
fi
fi
fi
-
fi
fi
fi
(1
0)+(
11)
(8)+
(9)
-
1951 fi fi fi 5,1 . fi (3) 4,6 . fi (5). 1971 fi 8,5 7 .
(8), (9) (10) fi fi 18 fi. (11) fi - 18 , (12) - .
1971 402. . ( Sauvy 7 - ).
-, , fi, - fi fi fi fi.
.fi fi fi fi fi fi fi. fi .
fi ( fi) .12
fi fi - fi fi 6.841.537 . fi fi fi fi 21 fi 1 . fi.
5.2. (1991-2000)
fi fi , , 1973-92 fi 28 . fi 1991 180 .
fi fi 470 . 1993, 76 fi, fi ( ).
fi fi - 1993 400 , fi - 300-500.000 fi.13 fi -. , ,, , , .
, fi fi - fi fi 1991-2000 200.000
44 E E E , Vol VIII, No 1, 2003
-
800.000 fi, fi , , , .. fi 1970, fi , fi.
fi fi fi - fi , - fi -. fi:
(2) 2 fi , - (3) fi fi .14 (4) fi fi , (6) . ( fi (5), ).
(3) fi fi fi 1991 5,56., 2000 12,53 . . fi (4) fi fi fi fi fi fi
fi , - fi . (8) fi . ( (7) fi fi () ). 1991 fi 8% 28% 2000. (9) fi,
fi.
6.
fi . fi , .15
fi fi fi , fi 2-3 . fi fi -, , fi:
.
fi 1989-96 -, fi fi fi, fi , fi , .
fi (1997-2000) ,
: 1990-2000 45
-
. (, , , ). fi fi fi fi- fi fi 2000.
fi fi fi - " fi". fi fi fi - fi .16
fi - - ,17 fi fi fi . fi fi fi fi - .
2 (fi )
fi fi % fi - - $: fi
X E.
$
(1) (2) (3) (4)=(2)*(3) (5) (6) (7)(8)=(4)/(7)
(9)*100
1991 200 5,560 1112,0 182,3 6,1 14412,2 7,7 1112,0
1992 300 6,327 1898,1 190,7 10,0 16536,3 11,5 632,7
1993 400 7,094 2837,6 229,3 12,4 18825,6 15,1 709,4
1994 450 7,861 3537,5 242,6 14,6 21387,3 16,5 393,1
1995 500 8,628 4314,0 231,7 18,6 23914,0 18,0 431,4
1996 550 9,543 5248,7 240,7 21,8 26359,8 19,9 477,2
1997 600 10,381 6228,6 273,1 22,8 28835,0 21,6 519,1
1998 700 11,143 7800,1 295,5 26,4 31251,0 25,0 1114,3
1999 750 11,854 8890,5 305,6 29,1 33376,0 26,6 592,7
2000 800 12,530 10024,0 365,4 27,4 35712,0 28,1 626,5
: (2) (3): (2001),
(5): ,
(7): 1991-1997 , 1998-2000 (2001)
46 E E E , Vol VIII, No 1, 2003
-
fi fi - fi - .
.
2004. fi .18
fi fi: 1) fi fi 2000
2004 2000.19
2) .3) fi fi fi -
.4) , -
( ).
5) fi fi .
1. fi fi , , fi .
2. fi (1996).
3. Social Europe (1991). fi - , fi .
4. fi (1995), fi (1987)
5. fi fi fi. .. -fi fi 25% . fi , fi .
: 1990-2000 47
-
6. (1996). - fi , , , .
7. Kindleberger (1965). fi: " P. Rosenstein-Rodan fi fi . ", .
236.
8. A. Sauvy (1963).
9. (1995)
10. : (1995).
11. 1955, 1962, 1966 1969. fifi 1951-71 fifi .
12. . fi , , fi fi fi fi fi .
13. 7/11/93.
14. , fi 35%-65 % . (2001)
15. , , fi , .
16. fi fi fi - fi ( , fi fi fi fi), fi , - , , ..
17. fi: fi fi .. -, , fi - fi .
18. fi fi fi fi.
19. fi fi fi fi 800.000-1.000.000 - , .
48 E E E , Vol VIII, No 1, 2003
-
(1993) 7-11-1993.fi . . . (1995) -
: , 15, .fi .(1987) , .Kindleberger C.P. (1965). Emigration and
Economic Growth. Banca Nationale der La-
voro, Quart. Rev. pp. 235-254. . (1995) -
. fi . 302-312 . 106 . (1996) , , . . (2003) fi , fi Sauvy A.
(1963) Theorie gnrale de la population, vol 1, 2 Paris.Social
Europe (1991) Immigration of citizens from third countries into the
Southern
Member States of the European Community. A comparative survey of
the Situ-ation in Greece, Italy, Spain and Portugal
(Supplement).
: 1990-2000 49
-
fi . fi
. ...
- , - fi fi fi fi fi fi. fi fi, fi fi fi .
Abstract
This article examines the economic-market, social and
technological transformationsas well as the specific aesthetic
patterns that reshape the urban landscape during the lasttwo
decades (from the building scale until the street and urban unit
scale). In a followingstep, it is proposed an interpretation of how
the growing transportation and mainlycommunication networks
together with the prevailing marketing mechanisms influencethe
image, the function and the structure of the city and determine the
objectives and theefficiency of urban interventions and
planning.
fi ... 51
Vol. VIII, No 1, 2003, pp. 51-63
-
1. fi - fi
fi - fi - fi fi , fi - , - fi fi fi .
, fi -, , , fi fi fi . , , -, fi fi, fi fi fi . fi fi, - fi, fi-
fi fi -, fi fi .
, fi fi - , - fi fi fi fi fi fi 1. fi fi, - fi fi fi fi fi fi .
fi - - , fi , , .
, , - -fi, - fi fi fi fi, fi fi , - .
fi fi fi fi. fi fi fi-
52 E E E , Vol VIII, No 1, 2003
-
fi fi fi -, -fi fi. , fi fi - fi (fi.. fi ..., ), fi fi- fi fi
fi fi.
fi , fi fi fi -fi , fi fi (ethnic) fi ( ) , fi fi, , , fi -fi fi
- fi - fi . , - fi ( ) - fi.
, fi ( - - ) ( - ) fi fi, fi fi - fi ..., , - , -fi - fi . , fi
fi fi - ( ) fi- - 20 .
, , fi fi 2 , fi - 70 80 - 90, - fi
fi ... 53
-
fi, fi fi -, fi - 100 fi.
2. fi fi
fi fi , - , fi -fi -fi fi fi. fi, - fi .
fi fi- - fi fi fi fi, , fi -3 ( fi Docklands fi )4.
, fi fi fi . - fi fi - fi media, - fi ( fi ).
fi , fi, - , - - fi fi fi ... fi-. , , , , , fi, fi , fi fi, fi
fi fi fi fi - ..., fi fi fi -
54 E E E , Vol VIII, No 1, 2003
-
fi, fi fi (fi fi fi - fi). , fi fi fi (, , ,, , fi ...), -fi
fi.
, fi , : fi fi fi - - fi, - , fi fi ...
, fi , - fi fi fi fi . ( -, fi ).
fi, , fi , fi fi - fi , fi .. , - fi fi fi , - fi, fi (video
clips, ...). - (soundtracks). fi fi fi fi fi - fi fifi , fi fi fi
fi (, , , .).
fi , fi fi , fi . fi fi fi . , -, fi - fi fi
fi ... 55
-
fi fi fi fi - , fi5.
3. fi fi
fi fi fi fi, fi fi fi - fi, fi 6.
fi 70 fi fi - , fi -, fi - fi - . - fi (Greenpeace, fi ) - fi fi
7.
, (, ) - - . fi , fi - , fi8 - - fi, fi - fi- fi .
fi fi, 9 fi ( ) - , - fi fi.
56 E E E , Vol VIII, No 1, 2003
-
fi fi fi - fi fi 10.
fi fi, fi (.., ..., , fi, fi, modem,..), - fi fi (, , ...)11. fi
, fi fi fi , - fi .., fi, fi fi fi fifi ( , , , )12.
, fi, fi - - fi fi fi fi fi, fi.
) , fi , , fi fi fi - fi (fi, fi-, ) (, fax, E-mail, modem .). -
fi fi fi , fi , fi , fi , fi fi - .
fi fi (- fi fi fi ) fi fi - , fi fi ( - .. fi fi fi - - ).
fi fi fi fi, fi
fi ... 57
-
fi fi- fi fi fi fi fi fi, fi fi . fi fi fi - fi fi , -.
media (, - ), fi , -, fi, fi , - fi , - (-, , , , , - ...).
. ... - fi - fi , - , fi, fi fi fi fi, fi , - . fi fi, fi - fi
fi , - fi fi . fi, fi fi fi, , fi fi-, fi fi fi (), - , fi - .
fi fi fi fi - - fi fi , fi fi - . fi , - fi fi fi fi fi .
58 E E E , Vol VIII, No 1, 2003
-
) fi fi - (...), fi, , fi fi, - fi fi13 fi fi (fi, , -, fi,
).
fi fi fi , - fi , , fi .. fi fi fi fi, , fi - (), fi - fi fi
(...). - . -fi fi, , ... fi - fi, - . , , - - fi . fi, - fi (fi -
fi).
, fi fi - :
fi fi , fi ( ) , fi- fi .
fi , - fi fi fi - ( ) - fi fi - fi - - , -
fi ... 59
-
fi fi ( , fi).
fi fi- , - fi .
fi fi -fi fi fi .
fi , fi, fi fi fi fi , fi fi - fi - fi. , fi fi fi fi fi fi fi -
, fifi fi .
fi, , , , , ,, fi, , fi, , fi, fi, , , fi , , fi, - , fi fi.
60 E E E , Vol VIII, No 1, 2003
-
-
1. Jenks Ch., (1980), Post Modern Classicism. Introduction,
A.D., . 5/6, . 5. JeacksCh., (1996), , , . 27.Dal Francesco,
(1997), Co Mario Botta, Electa/Rizzai.
2. Samuel P., (1974) , . , .
3. Erasmus Intensive Program, Lille 11/3/93 21/3/93, . 2.2.4.
fifi , - fi ( ) (projects), fi . fi fi fi , - ( -fi , , ).
4. Ward Reg., (1994), - Docklands, . . , .
5. fi , -, . ( ., (1991), fi fi fi fi fi, ,2/91, . 25). fi fi -
, fi - fi . ., - ., ., (1994), , . -, . 307-333.
6. ., (1988), fi - . fi - , . . - , . 8., . 1,. 80.
7. fi . (24/07/1990) - fi , (90) 218, - 24/7/1990. , fi, (
1997). -, 19 , (24/11/1993). , . 17.fi , (10/7/1987), , fi . ,(
92), UNCED 92.
fi ... 61
-
8. fi, fi . fi fi fi fi - fi fi (fi, , fi, , - ..) fi , , -
.
9. fi ., (1997), fi fi, . , . 282-318, fi - , . - , fi , . fi ..
fi, fi fi fi slums, - . fineighbourhood unit fi . fi fi fi : unit
de voisinage Nachbarschaftseinheit. , fi fi - fi fi fi fi . - fi fi
fi fi fi. fi fi ( - fi ) fi fi . - . (1979), . 87-102 fifi (. ,
12,13 14 1972) Charles Mercher (1975), .148-173 Suzanne Keler
(1972) . 276-289. Kevin Lynch, (1992), The image ofthe city, the
MIT press. fi fi fi fi , Louvain la Neuve, - Louvain, . fi . ( -
1985), fi , ..., . 2, . 26.
10. fi ., fi ., (1989), , //. - , , . 144-148. .,(1993), , . , ,
.354.
11. fi ., (1997), .., . 423, fi fi fi fi - fi fi. -
62 E E E , Vol VIII, No 1, 2003
-
. fi (GlobalInformation Society).
12. Canter D., (1988), , , (. . fi), University Studio Press, .
Piaget ., (1974),Adaptation in tale et psychologie de l
intelligence, Herman Paris.
13. Castells Man, (1997), "The Rise of the Network Society",
V.1, Blackwell, . 398 401. fi .,(1997), .. . 422. (1993), , . , , .
369.
fi ... 63
-
fi fi fi:
. ...
fi fi fi - fi. fi fi fi fi . fi - fi, fi fi / fi -fi fi fi fi -.
fi - fi fi . fi- fi fi fi .
Abstract
On of the major challenges in valuing ground water is how to
integrate the hydrolog-ic and physical components of ground water
resources into a valuation scheme. An ap-propriate conceptual basis
for valuation identifies service flows as a central link
betweeneconomic valuation and ground water quantity and quality.
One prominent technique thatattempts to measure total value
including use and nonuse values is the contingent valua-tion
method. The contingent valuation method values are elicited
directly from individu-als via interviews or questionnaires in the
form of statements of maximum willingness to
fi fi fi: 65
Vol. VIII, No 1, 2003, pp. 65-76
-
pay or minimum willingness to accept compensation for
hypothetical changes in the en-vironmental goods such as
groundwater quantity or quality. The decision maker at-tempting to
value groundwater faces significant uncertainties regarding
hydrologic, insti-tutional, economic and human health aspects of
ground water management. Cost-benefitanalysis is a very powerful
tool within the decision making process and taking account
thesustainable principals.
1.
fi fi fi 3% fi fi fi . 98% - fi. fi fi fi 0.20%. fi fi fi fi - .
- fi . fi - - fi. - fi . fi fi fi .
fi fi fi , fi fi fi . - fi fi fi fi fi fi fi fi. - fi -fi fi. fi
: ) , ) fi- - ) fi fi - [1,2,3].
fi fi fi, -. fi [5]: ) -
66 E E E , Vol VIII, No 1, 2003
-
, , fi, , - fi , fi fi , ) fi - . fi fi fi fi fi fi -fi fi fi fi
fi. - fi - fi ) fi - fi fi , ) ) fi - fi fi [4]. fi fi / - fi [3].
- fi - . fi - fi - fi.
fi / fi fi - fi- fi -fi fi fi .
2. fi
fi fi - fi fi-. fi fi - . fi - fi fi - . fi, fi fi fi fi - . fi
fi . fi fi - fi - fi fi, fi , fi fi fi-
fi fi fi: 67
-
, , fi , fi . fi fi .
fi fi fi- fi fi, fi . fi - (fi ). fi fi fi . fi- fi [6]. -fi fi
:
) fi , , .
) fi - , fi fi , fi - fi .
) , fi , fi , fi , - fi.
fi (..) - (...) (..)
() = () + ()
fi fi , fi fi fi . fi (..), fi (..) fi (...)
()= ()+()+()
fi fi fi fi fi fi fi fi fi . (...) fi () () 1.
()=() + ()
68 E E E , Vol VIII, No 1, 2003
-
fi fi - fi ) fi - fi, ) fi - .
1: fi
3.
fi fi fi fi fi fi, . . fi . fi - .
fi fi . fi /, fi, , - fi fi - [7].
fi
fi
A
A
A
Yfi fi
fi fi
A
fi fi fi: 69
-
fi / fi - fi fi. fi fi fi ,
fi fi - fi fi . fi - , fi fi . - fi fi fi - fi fi fi- .
fi fi -fi fi fi fi. fi fi , ) fi - fi fi fi - , fi fi fi , ) fi
- fi . - fi fi fi.
fi fi fi fi - fi - fi. - fi fi fi fi fi -. fi fi - fi , fi fi .
- fi , fi fi fi - fi , fi .
- fi . - fi fi- fi fi .
70 E E E , Vol VIII, No 1, 2003
-
4. fi
fi fi . fi . - fi- fi - fi fi.
fi fi , fi fi -, fi [6]. fi [8]: ) fi , ) fi - , fi , ) fi fi -,
fi fi fi fi.
fi fi -fi . -: ) , ) fi - , ) fi ) fi - fi. [6]. fi fi fi fi fi
fi fi fi fi .
fi fi fi fi fi : ) fi , fi fi , ) fi , - fi fi -
fi fi fi: 71
-
fi, ) , -fi, ) fi fi, , - ) fi .
fi- fi fi fi fi fi fi fi. fi fi , - fi - fi [5]. - fi fi fi fi
(fi) fi -fi (fi). fi fi- , - fi fi 1983 - fi fi [9].
4.1. fi - :
fi fi fi fi/ [10]:
fi fi - fi (1)
(1)
fi, fi , i -, Ci fi, fi fi.
fi -fi, fi fi fi fi -fi fi fi (2)
(2){ /( )]} [ /( )]}[Bi1+ / { 1+i
Ni
ii o
NiC
= = >0
1
max{ /( )] [ /( )]}[Bi1+ 1+i
Ni
ii o
NiC
= = 0
72 E E E , Vol VIII, No 1, 2003
-
, fi - fi fi fi (3)
(3)
4.2. fi fi
fi fi fi fi fi. fi fi fi ) fi , ) fi , , fi .
fi fi - fi , fi (- -), : ) , ) fi , ) - fi , ) -. fi fi-- [6]: )
fi fi , ) fi - fi , ) fi - fi fi fi, ) fi , fi -.
fi - fi fi fi . fi fi-. fi fi- - [11]:
(4)
fi, j j, Bj(t)
j j{1 1+ [B= ={ /( )] () () ()]}t
Tt
j jt C t R t0
{ /( )] [ /( )]}[Bi1+ 1+i
Ni
ii o
NiC
= = >0
0
fi fi fi: 73
-
j t, Cj(t) fi j t, Rj(t) fi fi j t, T fi fi fi.
fi fi fi - (5):
(5)
fi, Pf (t) fi t, Cf (t) fi fi t, (Cf) fi- fi . fi fi fi - , -
-fi. >1 fi ,=1 fi.
5.
fi fi fi fi. fi fi, fi fi fi [10]. -fi fi fi- fi .
fi fi fi . fi fi fi , fi fi fi -fi fi fi fi - fi fi fi , , fi fi
. fi fi fi - fi . - fi fi . fi fi fi fi fi -fi fi fi fi fi fi - .
-
R t t() () () ( )= P t C Cf f f
74 E E E , Vol VIII, No 1, 2003
-
fi fi fi fi - fi fi fi. fi fi fi fi , fi fi fi fi fi fi fi fi
fi- fi .
6. fi -
fi fi- . - , fi - fi. , - fi fi, fi - . fi - fi fi -. fi- fi -fi
fi fi - fi. - fi fi fi , - . fi fi .
fi fi - fi fi . - fi fi fi fi fi .
fi fi fi: 75
-
1. Anastasiadis P., (2001) Groundwater quality modelling for
non-point sources, JournalFresenius Environmental Bulletin, vol. 10
(5) pp. 506-511.
2. ., (1994) fi fi fi . , .
3. Field B.C, (1997), Environmental economics. An introduction,
McGraw Hill4. Turner P.K., Pearce D., and Batemen I., (1994)
Environmental economics. An ele-
mentary introduction, Herverter Wheatsheaf5. Environmental
Protection Agency (1995), A framework for measuring the
economic
benefits of groundwater, EPA6. Pearce D.W. and Turner R.K.,
(1990), Economics of natural resources and the envi-
ronment, Herverter Wheatsheaf7. National Research Council,
(1997), Valuing groundwater. Economic concept and ap-
proaches, National Academy Press.8. Hoehn J.L., (1992), The
earthscan reader in environmental economics, (Eds A.
Markandya and J. Richardon, Earthscan Publication9. Griffin
R.C., (1998), The fundamental principles of cost-benefit analysis,
Water re-
sources research, vol.