None

Thesis (M. S.)--Electrical and Computer Engineering, Georgia Institute of Technology, 2010. / Committee Chair: Cressler, John; Committee Member: Citrin, David; Committee Member: Shen, Shyh-Chiang. Part of the SMARTech Electronic Thesis and Dissertation Collection.

Extreme environment applications impose stringent demands on technology platforms that are incorporated in electronic systems. Space is a classic extreme environment, encompassing both large temperature fluctuations as well as intense radiation fields. Silicon-germanium technology has emerged as a competitive platform for space-based applications, owing to its excellent low-temperature performance and total ionizing dose tolerance. This technology has however been repeatedly shown to be vulnerable to single event phenomena induced by galactic cosmic rays as well as trapped particles within the earth's geomagnetic field. To improve the radiation tolerance of systems incorporating SiGe components, modifications to fabrications steps (Radiation Hardening by Process, RHBP) and/or device/circuit topologies (Radiation Hardening by Design, RHBD) may be employed. For this thesis, two methodologies are analyzed, both RHBD techniques which come at no additional power/area penalty for implementation.

Bakgrund och problemdiskussion: Familjeföretag är oftast i behov inom olika områden av ett externt stöd som är oberoende från familjen och företaget. Revisorer och externa styrelseledamöter är två exempel som kan vara mycket värdefulla aktörer att ha i familjeföretag. Tidigare forskning som är relaterad till ämnet har undersökt antingen endast rollerna för externa styrelseledamöter inom familjeföretag eller bara revisorns roller i familjeföretag. Ingen tidigare forskning har dock diskuterat båda aktörernas roller tillsammans och undersökt om det finns en substitutions- eller komplementeffekt mellan de i små medelstora familjeföretag. Detta ger oss motivationen att bidra till forskning, genom att öka förståelse kring både aktörernas fyra roller inom familjeföretag och undersöka effekterna som uppstår mellan de.  Syfte: Syftet med denna uppsats är att öka förståelsen för de rollerna som revisorer och externa styrelseledamöter har i ett familjeföretag, för att därmed utveckla kunskap om huruvida revisor kan substituera vissa roller som en extern styrelseledamot kan inneha, eller om både parter kompletterar varandra med sina roller i familjeföretag.   Metod: Deduktiv forskningsansats har använts, där uppsatsens teoretiska modell byggts upp utifrån befintliga teorier och forskning kring ämnet. En kvalitativ studie genomförts genom semistrukturerade intervjuer med ägare/VD i små och medelstora familjeföretag, för att få en förståelse för deras perspektiv på revisorns och externa styrelseledamöters roller samt eventuella effekter i familjeföretag.  Resultat och slutsats: Studien har kunnat påvisa att det förekommer en substitutions- och komplementeffekt mellan de olika aktörerna. Rollerna och effekterna varierade mellan olika familjeföretag. Detta är till följd av att familjeföretagen hade olika omständigheter och förväntningar på rollerna som skiljer sig åt i respektive familjeföretag. Dessa skillnader kunde vi identifiera genom olika faktorer som lyfts fram. / Background and problem discussion: Family businesses are usually in need in various areas of external support that is independent from the family and the company. Auditors and external board members are two examples that can be very valuable actors to have in family businesses. Previous research related to the topic has examined either only the roles of outside directors in family firms or only the roles of the auditor in family firms. However, no previous research has discussed the roles of both actors together and investigated whether there is a substitution or complementarity effect between them in small medium-sized family businesses. This gives us the motivation to contribute to research, by increasing understanding around both the actors' four roles within family businesses and investigating the effects that arise between them.  Purpose: The purpose of this essay is to increase understanding of the roles that auditors and external board members have in a family business, to thereby develop knowledge about whether the auditor can substitute certain roles that an external board member can hold, or whether both parties complement each other with their roles in family businesses.  Method: A deductive research approach has been used, where the essay's theoretical model has been built up based on existing theories and research on the subject. A qualitative study was conducted through semi-structured interviews with owners/CEOs in small and medium-sized family businesses, to gain an understanding of their perspective on the roles of the auditor and external board members as well as possible effects in family businesses.  Results and conclusion: The study has been able to demonstrate that there is a substitution and complementation effect between the various actors. The roles and effects varied between different family businesses. This is because the family businesses had different circumstances and expectations of the roles that differ in each family business. We were able to identify these differences through several different factors that were highlighted.

This study shows that a concurrent active noise control strategy for engine harmonics and road noise has a complementary effect. In particular, we found that engine booming noise is additionally attenuated when road noise control is concurrently used with engine harmonics control; an additional attenuation of 2.08 dB and 1.25 dB for the C1.5 and C2.0 orders, respectively, was achieved. A parallel multichannel feedforward controller for non-stationary narrowband engine harmonics and broadband road noise was designed and implemented to reduce noise in all four seats. Two control signals were considered independent because the reference signals, engine revolution speed for the engine harmonic controller, and acceleration signal for the road noise controller are uncorrelated. However, if the reference sensor for the road noise controller is installed along the overlapping transfer path between the engine noise and road noise, the engine noise may also be suppressed by the control signal for the road noise attenuation. Based on transfer path analyses for both engine harmonics and road noise, the optimal positions for the reference sensors were selected. In addition, we identified several overlapping transfer paths between the engine booming noise and road noise. A practical active noise control system combined with a remote microphone technique was implemented for a large six-cylinder sedan using a vehicle audio system to evaluate the noise attenuation performance. The experiments showed that the interior noise from the engine and road excitation was effectively suppressed by the proposed concurrent control strategy..

This thesis investigates the effects of low temperatures on Silicon Germanium (SiGe) Hterojunction Bipolar Transistors (HBT) BiCMOS technology. A comprehensive set of dc measurements were taken on first, second, third and fourth generation IBM SiGe technology over a range of temperatures (room temperature to 43K for first generation, and room temperature to 15K for the rest). This work is unique in the sense that this sort of comprehensive study of dc characteristics on four SiGe HBT technology generations over a wide range of temperatures has never been done before to the best of the authors knowledge.