MixedLevelRSDs - Mixed Level Response Surface Designs
Response Surface Designs (RSDs) involving factors not all
at same levels are called Mixed Level RSDs (or Asymmetric
RSDs). In many practical situations, RSDs with asymmetric
levels will be more suitable as it explores more regions in the
design space. (J.S. Mehta and M.N. Das (1968)
<doi:10.2307/1267046>. "Asymmetric rotatable designs and
orthogonal transformations").This package contains function
named ATORDs_I() for generating asymmetric third order
rotatable designs (ATORDs) based on third order designs given
by Das and Narasimham (1962). Function ATORDs_II() generates
asymmetric third order rotatable designs developed using
t-design of unequal set sizes, which are smaller in size as
compared to design generated by function ATORDs_I(). In
general, third order rotatable designs can be classified into
two classes viz., designs that are suitable for sequential
experimentation and designs for non-sequential experimentation.
The sequential experimentation approach involves conducting the
trials step by step whereas, in the non-sequential
experimentation approach, the entire runs are executed in one
go (M. N. Das and V. Narasimham (1962)
<doi:10.1214/AOMS/1177704374>. "Construction of Rotatable
Designs through Balanced Incomplete Block Designs").
ATORDs_I() and ATORDs_II() functions generate non-sequential
asymmetric third order designs. Function named SeqTORD()
generates symmetric sequential third order design in blocks and
also gives G-efficiency of the given design. Function named
Asymseq() generates asymmetric sequential third order designs
in blocks (M. Hemavathi, Eldho Varghese, Shashi Shekhar and
Seema Jaggi (2020) <doi:10.1080/02664763.2020.1864817>.
"Sequential asymmetric third order rotatable designs
(SATORDs)"). In response surface design, situations may arise
in which some of the factors are qualitative in nature (Jyoti
Divecha and Bharat Tarapara (2017)
<doi:10.1080/08982112.2016.1217338>. "Small, balanced,
efficient, optimal, and near rotatable response surface designs
for factorial experiments asymmetrical in some quantitative,
qualitative factors"). The Function named QualRSD() generates
second order design with qualitative factors along with their
D-efficiency and G-efficiency. The function named
RotatabilityQ() calculates a measure of rotatability (measure
Q, 0 <= Q <= 1) given by Draper and Pukelshiem(1990) for given
a design based on a second order model, (Norman R. Draper and
Friedrich Pukelsheim(1990)
<doi:10.1080/00401706.1990.10484635>. "Another look at
rotatability").