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Reviews
Two alternative versions of strangeness
Kazuhiko NISHIJIMA
Overview on the applications of random wave concept in coastal engineering
Yoshimi GODA
Original Papers
Cysteine-390 is the binding site of luminous substance with symplectin, a photoprotein from Okinawan squid, Symplectoteuthis oualaniensis
Minoru ISOBE, Masaki KUSE, Naoki TANI, Tatsuya FUJII and Tsukasa MATSUDA
Genetic dissection of testis weight in a mouse strain having an extremely large testis: major testis weight determinants are autosomal rather than Y-linked on the basis of comprehensive analyses in Y-chromosome consomic strains
Jun-ichi SUTO
Cover Illustration
A close-up view of ocean waves showing very complicated structure.
The photograph is a close-up view of ocean waves in the North Atlantic Ocean. The waves
clearly show complex and multiple structures; there are various small-sized waves superimposed on
a large dominant wave and the large dominant wave itself shows very complicated form which is
much different from a sinusoidal form. Furthermore, if we look at such waves widely for a long time
the waves change randomly with space and time.
Until the middle of the twentieth century such a complex structure of ocean waves deterred
scientists and engineers from studying their dynamics and from developing mathematical models. In
fact, it is said that Lord Rayleigh (1842-1919) considered the mathematics involved in representing
real ocean waves and remarked, “The basic law of the sea way is the apparent lack of any law”.
On the basis of great many studies over more than half a century, we now know that ocean
waves are composed of infinitely many wave components of random phases concentrated around the
dominant wave components, and the wave components are interacting weekly through nonlinear
processes. We generally measure the distribution of energy in wave components in terms of a ‘wave
spectrum’. The concept of the wave spectrum introduced in the 1950s greatly advanced our
understanding of ocean waves which show partly random and partly regular characteristics.
There is another interesting but difficult problem on the ocean waves: their energy transfer
processes. Ocean waves are generated by sea surface wind through a complicated process of energy
transfer from the wind to the waves. On the other hand, the ocean waves loose a part of their energy
through wave breaking. Furthermore, wave components exchange part of their energies through
nonlinear wave-wave interactions. Therefore, in order to predict the ocean waves under the wind
action we need to know these fundamental processes.
Although there still remain various difficult problems in these fundamental processes, our
understanding on the processes has been greatly advanced. On the basis of such advancement,
Professor Yoshimi Goda and many engineers have endeavored to develop and refine the technology
for dealing with wave actions on structures. The review in the present issue describes the
development of engineering applications of the random wave concept for planning and design of
maritime structures in the last several decades. The review can be regarded as an example of
successful collaboration between scientists and engineers.
This cover photograph has been used by Y. Goda "A review on statistical properties of sea
waves" (Proc. Jpn. Soc. Civil Eng. 357, 1985) and H. Mitsuyasu "Looking Closely at Ocean Waves
-from their birth to death-"(Iwanami Shoten Publishers, 2007).
Hisashi Mitsuyasu
Professor Emeritus
KyushuUniversity
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