It is possible to reduce residual and maximum drifts in buildings by adding “elastic stories” that engage gravity columns in seismic response. An elastic story is a story wherein the buckling restrained brace frame (BRBF) size is increased to prevent yielding when an earthquake occurs. Buildings ranging from 4–16 stories were designed with various elastic story brace sizes and locations to determine the optimal combination to best reduce drifts. Gravity column stiffnesses were also varied in elastic story buildings to determine the effects on drifts. Computer models were used to analyze these buildings under a suite of earthquakes. Adding elastic stories reduce residual drifts 34% to 65% in 4- to 16-story BRBF buildings. General recommendations are made to achieve optimal reductions in drifts. For buildings with six or more stories, drifts were generally reduced most when an elastic story was added to every 4th story starting at level 1 (the bottom story). The most effective size for the braces in the elastic story appears to be three times the original brace size. For buildings with less than six stories, adding a three times elastic story to the bottom level was observed to reduce drifts the most. Further research is also recommended to confirm the optimal location and size of elastic stories for buildings with differing number of stories. Increasing gravity column stiffnesses in buildings with elastic stories helps to further reduce drifts, however it may not be economical. Residual drifts were observed to decrease significantly more than maximum drifts when elastic stories were added to buildings. Maximum drifts generally decreased at some levels, but also increased at others when elastic stories were used.

Post Earnings Announcement Drift (PEAD) är en marknadsanomali som innebär att aktiepriser driftar i samma riktning som resultatöverraskningar under en period efter publicerad kvartalsrapport. Denna studie undersöker om PEAD existerar på Stockholmsbörsen under de efterföljande 10 respektive 60 handelsdagarna efter publicerad kvartalsrapport. Undersökningen av PEAD genomfördes med en eventstudie under tidsperioden 2013-2019. Huvudresultatet kan inte konstatera att PEAD återfinns på Stockholmsbörsen. Vid separat analys av Large Cap och Small Cap påvisas PEAD för stora bolag 60 handelsdagar efter publicerad kvartalsrapport för positiva resultatöverraskningar. För negativa resultatöverraskningar konstateras istället en omvänd (positiv) drift i aktiepriser för stora bolag. Små bolag påvisar en svagt signifikant positiv drift i samma riktning resultatöverraskningen de efterföljande 60 handelsdagarna. Studien tyder på att företagsstorlek kan påverka driften i aktiepriser. Det fastställs även att en hedgeportfölj för små bolag kan generera en signifikant överavkastning. Sammanfattningsvis kan studien inte fastställa att PEAD existerar på Stockholmsbörsen.

Trafikverkets drift- och underhållsentreprenader "basunderhåll väg" anses av entreprenörerna ha en obalanserad riskfördel. Huvudfrågan är om totalentreprenad är den bästa lösningen på Trafikverket driftkontrakt på vägsidan. Examensarbetet har utförts tillsammans med NCC. Datainsamlingen har gjorts dels genom litteraturstudier och dels genom intervjuer med Trafikverket, Sveriges Byggindustrier samt de stora entreprenörerna Svevia, NCC, Peab och Skanska. Slutsatsen av arbetet är att kontrakten innehåller för många oklarheter för att upphandlas på totalentreprenad, men får Trafikverket kontroll på mängder som ska utföras framöver är det fullt möjligt att upphandla kontrakten på totalentreprenad. Däremot kommer det inte att hinnas med någon inventering av mängderna inför kommande upphandling. Av den anledningen föreslås att kontrakten 2018 upphandlas som samverkansentreprenad utan incitamentsavtal under de två första åren då entreprenören tillsammans med Trafikverket inventerar och planerar vad som ska utföras under den fyraåriga kontraktstiden. Inför tredje och fjärde året görs ett incitamentsavtal 50/50 när omfattningen är mera känd. / Trafikverket:s Road maintenance contracts, "Basunderhåll väg", is considered by the contractors to have an uneven distribution of risk between the partners. The main question is if Design-build contract is the best solution for Trafikverket:s Road maintenance contracts on the roadside. The essay has been written on behave of NCC account. The study is based upon literature studies, but also by interviewing staff from big companies, whom are affected by these contracts (Trafikverket, Sveriges Byggindustrier, NCC, Svevia, Peab, Skanska). The main conclusion with the essay is that the contracts maintain too many uncertainties to be procured at a Design-build contract. However, if Trafikverket manages to control the amount mass data, it is highly possible to procure contracts with Design-build contract contracts in the near future. Although, it will not be obtainable to have some sort of inventory of these amounts for the upcoming procurements. By this reason, the proposal is Partnering contract procured by 2018 without any incentives during the first two years. Both the contractors and Trafikverket plan the inventory of what shall be done during the four-year contract period. For the third and the final year they shall make an agreement on a target price for the incentive 50/50 when the extent is better known. Key

Trafiksäkerheten för cyklister vintertid är beroende av bra friktion, god framkomlighet och välplanerad cykelinfrastruktur. För att cyklandet ska kunna ske året om är det viktigt att kunna erbjuda cyklisterna säkra vägar vintertid. Genom olika driftmetoder kan cykelvägarna göras framkomliga även vid kyla och snöfall. I studien har metoderna konventionell snöröjning, sopsaltning och markvärme studerats. I Stockholms stad har utvalda cykelstråk sedan vintern 2013/2014 sopsaltats för att fler ska välja cykeln på vintern. Ytor i centrala delar av staden med högt fotgängarflöde värms idag upp av markvärme. Konventionell snöröjning med plog och sand används på gångytor och övriga cykelvägar. Dessa driftmetoder ger varierande resultat för framkomlighet och trafiksäkerhet. Cykelvägarna genom Slussenområdet är högt trafikerade då de binder ihop stadens cykelstråk från olika stadsdelar. Stockholms stad vill att cykeltrafiken ska öka ytterligare, vilket är något som läggs stor vikt vid ombyggnationen av Slussen. I rapporten har utformning av de nya cykelvägarna granskats och analyserats för att identifiera riskområden vintertid. Analysen bygger på tidigare mätningar, undersökningar och rapporter. Riskområdena är identifierade utifrån potentiell olycksrisk för cyklister, framkomlighet och drifteffektivitet. Förslag på vilken eller vilka av driftmetoderna som är mest lämplig har getts för varje område. Analysen visar på att det är bra om cykelvägarna sopsaltas. Där det förekommer många gångtrafikanter tillsammans med cyklister är det lämpligt att anlägga markvärme. Att sanda cykelvägarna är inte ett bra alternativ. Analysen visar även att det finns flera områden som kommer att vara problematiska för cyklisterna på vintern. / Road safety for cyclists during winter is dependent on good friction, good accessibility and well-planned cycling infrastructure. In order for cycling to happen throughout the year, it is important to offer cyclists safe roads even during winter. Through different operating methods, the cycleways can be made available even at low temperature and snowfall. In this study three different methods for snow clearance and skid control have been studied. Stockholm City uses the method of power broom and brine for de-icing on selected cycleways with high priority since the winter of 2013/2014. Other cycleways are cleared from snow through ploughing and skid control is done by gritting. Snow melting systems are installed in central parts of the city where heated ground gives the pedestrians a snow-free surface. The cycleways across Slussen have a high frequency of people travelling by bicycle because it ties cycleways from different parts and the city together. Stockholm City wants to promote bicycle travelling in the area that currently is undergoing rebuilding. In the report, the design of the new cycleways has been reviewed and analyzed to identify risk areas in winter. The analysis is based on previous measurements, surveys and reports. Risk areas are identified based on potential risk of accidents for cyclists, accessibility and operational efficiency. Proposals for which of the operating methods that are most appropriate have been given for each area. The analysis shows that the power broom-method is a good option. In areas where there are many pedestrians along with cyclists, it is advisable to install a snow melting system. Gritting the cycleway is not a good option. The analysis also shows that several areas will be problematic for cyclists in the winter.

To gain an understanding of the ecology of drift algae in the Indian River Lagoon system along the east coast of central Florida, four questions were addressed: 1) What is the composition and rate of accumulation of drift? 2) How much movement and turnover occurs within drift accumulations? 3) Do growth rates differ for drift versus attached algae? 4) Is there a difference in photosynthetic performance in drift versus attached algal species? Manipulative field and laboratory experiments were conducted to address these questions with the green macroalga Codium decorticatum and the red macroalga Gracilaria tikvahiae. Changes in pigment concentration and biomass were used as indicators of acclimation from an attached to drift state in Gracilaria tikvahiae and Codium decorticatum. Short-term physiological changes as demonstrated by electron transport rate (ETR) were also used as indications of acclimation from an attached to drift state in C. decorticatum. Composition and rate of accumulation of drift varied by season. While both transport and turnover of drift occurred, turnover within drift accumulations occurred at low rates and was significantly lower in the spring during decreased flow rates. There were no significant differences in growth or pigment concentrations in drift versus attached G. tikvahiae or C. decorticatum. In addition, there were no apparent physiological acclimations to a drift state in C. decorticatum.

An intensive, replicated monthly sampling of snake communities inhabiting four habitat types was conducted at John F. Kennedy Space Center, Brevard County, Florida from November 2002 through October 2003. Thirteen species (580 individuals plus 74 recaptures) plus one hybrid were captured. The three most commonly captured species, Coluber constrictor, Thamnophis sirtalis, and Thamnophis sauritus, combined made up 85% of the sample. These three species were active during every month of the year, but showed modal activity patterns typical of Temperate Zone snakes. Monthly snake captures were correlated with monthly captures of potential prey species and with mean monthly temperature. Species richness in the four habitat types varied from nine to 12. Drift fences in ruderal habitats had the highest species richness, while fences in swales captured the greatest number of individuals. The most dissimilar habitat pair was scrub and swale, while the most similar pair was ruderal and hammock. Box traps proved more effective for targeting the largest snake species, while funnel and box traps were equally effective for targeting other species.

This thesis presents the details of a study regarding both the use of linear viscous fluid dampers in controlling the interstory drift in steel moment frames, and the use of incremental dynamic analysis as a method of visualizing the behavior of these moment frames when subjected to seismic load effects. Models of three story and nine story steel moment frames were designed to meet typical strength requirements for office buildings in Seattle, Washington. These models were intentionally designed to violate seismic interstory drift restrictions to test the ability of the linear viscous fluid dampers to reduce these drifts to the point of code compliance. Dampers were included in one bay of every story in each model. These devices were used to produce total structural damping ratios of 5%, 10%, 20%, and 30% of critical. Undamped, traditional stiffness controlled models of both three stories and nine stories were also created for comparison purposes. Incremental dynamic analysis was used to subject these models to ten ground motions, each scaled to twenty incremental levels. Two new computer applications were written to facilitate this process. The results of these analyses were studied to determine if the linear viscous fluid dampers were able to cause compliance with codified drift limits. Also, incremental dynamic analysis plots were created to examine the effects of the dampers on structural behavior as damping increased from inherent to 30% of critical. It was found that including linear viscous fluid dampers in steel moment frame design can satisfactorily control interstory drift, and incremental dynamic analysis is a beneficial tool in visualizing dynamic structural behavior. / Master of Science

This thesis is divided into two topics: the development of a procedure for wind serviceability design of steel buildings and the development of a simple linear response history analysis for building codes. In the United States the building codes are generally silent on the issue of serviceability. This has led to a wide variation in design practices related to service level wind loads. Chapter 2 of this thesis contains a literature review which discusses pertinent aspects of wind drift serviceability, including selecting the mean recurrence interval (MRI), mathematical modeling of the structure, and establishment of rational deformation limits. Chapter 3 contains a journal article submitted to Engineering Journal which describes the recommended procedure for damage based wind serviceability design of steel structures. The procedure uses a broad range of MRIs, bases damage measurement on shear strains, includes all sources of deformation in the model, and bases deformation limits on fragility curves. Chapter 4 of this thesis contains a literature review which examines issues related to performing linear response history analysis. Chapter 5 contains a conference paper submitted to the Tenth U.S. National Conference on Earthquake Engineering which serves as a position paper promoting the inclusion of a linear response history analysis procedure in future editions of the NEHRP Recommended Seismic Provisions and ASCE 7. The procedure address the following issues: selection and scaling of ground motions, the use of spectral matched ground motions, design for dependent actions, and the scaling of responses with the response modification coefficient (R) and the deflection amplification factor (Cd). / Master of Science

This article presents a simulation study into effects of compliant (flexible) components (such as the engine subframe and the lower control arm) and their deflections on the characteristics of a vehicle experiencing steering drift during straight-line braking. The vehicle front and rear suspension are modelled using multi-body dynamic analysis software. The front suspension model represents theMacPherson strut design of the vehicle and includes a rack and pinion steering system, brake system, engine subframe, and a powertrain unit. The model has been analysed under two steering control methods: fixed and free control. Suspension characteristics and the effect of deflections arising from the subframe and the lower control arm on these suspension characteristics have been analysed. The simulations confirmed that variation of component stiffness and interactions within components give rise to side-to-side deflections that could affect lateral drift during braking. It is concluded that side-to-side variation of suspension characteristics can have a detrimental effect on lateral drift during braking and that compliant components whose stiffness varies from side to side can cause different side-to-side deflections that can induce and influence variation in suspension characteristics such as toe steer angle that can lead the vehicle during braking.

The presence of outlying anchor items is an issue faced by many testing agencies. The decision to retain or remove an item is a difficult one, especially when the content representation of the anchor set becomes questionable by item removal decisions. Additionally, the reason for the aberrancy is not always clear, and if the performance of the item has changed due to improvements in instruction, then removing the anchor item may not be appropriate and might produce misleading conclusions about the proficiency of the examinees. This study is conducted in two parts consisting of both a simulation and empirical data analysis. In these studies, the effect on examinee classification was investigated when the decision was made to remove or retain aberrant anchor items. Three methods of detection were explored; (1) delta plot, (2) IRT b-parameter plots, and (3) the RPU method. In the simulation study, degree of aberrancy was manipulated as well as the ability distribution of examinees and five aberrant item schemes were employed. In the empirical data analysis, archived statewide science achievement data that was suspected to possess differential opportunity to learn between administrations was re-analyzed using the various item parameter drift detection methods. The results for both the simulation and empirical data study provide support for eliminating the use of flagged items for linking assessments when a matrix-sampling design is used and a large number of items are used within that anchor. While neither the delta nor the IRT b-parameter plot methods produced results that would overwhelmingly support their use, it is recommended that both methods be employed in practice until further research is conducted for alternative methods, such as the RPU method since classification accuracy increases when such methods are employed and items are removed and most often, growth is not misrepresented by doing so.