Thesis (Ph. D.)--Lehigh University, 2004. / In two parts. Includes vita. Includes bibliographical references (leaves 545-550).

Thesis (M.S.)--Oregon State University, 2004. / Typescript (photocopy). Includes bibliographical references (leaves 82-104). Also available via the World Wide Web.

Thesis (M.S.)--California Polytechnic State University, 2009. / Title from PDF title page; viewed on Sept. 16, 2009. "August 2009." "In partial fulfillment of the requirements for the degree [of] Master of Science in Civil and Environmental Engineering." "Presented to the faculty of California Polytechnic State University, San Luis Obispo." Major professor: Charles B. Chadwell, Ph.D. Includes bibliographical references (p. 67-71).

Thesis (Ph.D.)--Drexel University, 2010. / Includes abstract and vita. Includes bibliographical references (leaves 449-468).

Thesis (Ph. D.)--Drexel University, 2006. / Includes abstract. Includes bibliographical references (leaves 230-242).

Thesis (M.E.)--University of Canterbury, 2006. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Thesis (M.E.)--University of Canterbury, 2005. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

When analysing volcanic seismicity and volcanic events, it is often interesting to focus on tremor, which is a signal of long duration. This is because not much is known about tremor. Unlike earthquakes, sources of tremor are difficult to locate due to them not having any clear onsets in the seismic signal. Different location methods can be used to attempt to locate tremor sources, one of which incorporates correlation of seismic signals between two different recording stations. This method is sensitive to the frequency content in the signal, and will not operate correctly if the signal consists of non-tremor signals, e.g. earthquakes. Earthquakes generally contain higher frequencies than tremor, and if these are present in the signals being correlated, this will affect the location method negatively. Therefore, it is desirable to try to detect these events containing other frequencies, to be able to remove them from the data and improve the location method. Constructing this method is the objective of the study, and is done using the programming language Matlab. The method uses correlation between the amplitude spectra of short adjacent time intervals of the bigger time series, in an attempt to detect when the spectral signature of the time series radically changes. An outlier is deemed to exist when the correlation coefficient from the comparison falls beneath a pragmatically chosen multiple of standard deviation from the mean of coefficient values. The objective of the study has been achieved, by constructing a method using correlation between time intervals to detect sudden fluctuations in the spectral shape of the time series. The method does seem promising, however, the accuracy of the method now needs to be rigorously tested. Time has not allowed for this to be done in this study, and is left for future research. / När man analyserar vulkaniska händelser och seismik är det ofta intressant att fokusera på tremor, vilket är långvariga händelser. Detta är p.g.a. att inte mycket är känt om des-sa. Till skillnad från jordbävningar, så är orsaken till tremor svår att lokalisera eftersom dom inte har en tydlig början i den seismiska signalen. Olika lokaliseringsmetoder kan användas för att försöka lokalisera dessa orsaker, varav en är en metod som använder sig av korrelationen mellan den seismiska signalen för två olika mätstationer. Denna metod är känslig för innehållet av frekvens i signalen som används i jämförelsen, och kommer inte fungera lika bra om signalerna innehåller annat än endast tremor, t.ex. jordbävningar. Jordbävningar innehåller generellt högre frekvenser än tremor, och ifall dessa är närvarande i signalerna som används i jämförelsen kommer detta påverka metoden negativt. Därför är det önskvärt att försöka hitta dessa händelser som ger upphov till andra frekvenser, för att sedan kunna avlägsna dessa och förbättra lokaliseringsmetoden. Målet med detta projekt är därmed att konstruera denna metod, och detta genomförs i programmeringspråket Matlab. Metoden använder sig av korrelation mellan amplitudspektrum av korta närliggande tidsintervall från den större tidsserien, för att försöka detektera när frekvensinnehållet i signalen ändras radikalt. Ett interval anses vara en avvikelse närkorrelationskoefficienten från jämförelsen faller under en pragmatiskt vald multipel av standardavvikelsen av medelvärdet av korrelationskoefficienterna.Målet med projektet har uppfyllts, genom att konstruera en metod som använderkorrelation mellan tidsintervall för att detektera plötsliga fluktuationer av dom frekvensersignalen innehåller. Metoden verkar lovande, men noggrannheten av den behöver nu testas rigoröst. Tyvärr kunde inte detta utföras inom tidsgränserna av detta projekt, och får lämnas som framtida forskning.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第18226号 / 工博第3818号 / 新制||工||1585(附属図書館) / 31084 / 京都大学大学院工学研究科都市社会工学専攻 / (主査)教授 清野 純史, 教授 三村 衛, 准教授 古川 愛子 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Base isolated buildings are well known to provide enhanced performance due to minimized accelerations and decreased interstory drifts. However, the reduced demands are obtained at the expense of large displacements at the isolation layer. This study investigates an innovative system, termed ‘dual isolation’, which applies two layers of isolation, one at the base and one mid-story to resolve this issue. An analytical solution for the equation of motion of the proposed system is developed based on linear isolation theory. This creates a foundation to assess the behavior of various types of seismic protection systems and to select the damping, mass and frequency ratio that leads to an optimal dual isolation design. Time history responses of the dual isolation system with viscous damping are compared to those of a conventional isolation counterpart to examine the effectiveness of the system. The system reduces first floor displacements by 40% on average, while the roof displacement is increased by roughly 15%. This results in reduced design forces for the structure. In addition, accelerations, especially above the second isolation layer, are significantly decreased. By reducing story shears and accelerations, the dual isolation system limits damage to both structural and nonstructural systems and components, thereby increasing global system performance. / Thesis / Master of Applied Science (MASc)