A Perspective on Arkansas Basin and Ozark Highland Prehistory

It is, from time to time, valuable to reassess and perhaps shed new light on long-held perspectives. In The \u27Northern Caddoan Area\u27 was not Caddoan, Frank Schambach provides a provocative reinterpretation of the archaeology of the Arkansas Basin and Ozark Highland regions of Oklahoma, Arkansas, and Missouri. While certain comments in this paper have merit and deserve deeper consideration, the central theme and supporting arguments are severely flawed, both from conceptual and data points of view. Schambach\u27s central argument is that there were no Caddoans in the Arkansas Basin and Ozark Highlands north of Spiro. To make this point he asserts that the only Caddoan site north of the Ouachita Mountains is the Brown Mound group at Spiro. All the other sites in the region, including the Craig Mound group at Spiro, are not Caddoan, but are instead a currently undefined Mississippian manifestation. Schambach\u27s scenario goes. something like this: Mississippians moved up the Arkansas River valley in the early,Mississippian Period (presumably in the Harlan Phase, A.O. 850-1250), through western Arkansas to eastern Oklahoma where they displaced the Caddoans living at the Brown Mound group. The Caddoans moved back south to the Ouachita Mountains. The Mississippians, including people of the Plum Bayou culture ... the Spiro phase [A.O. 1250-1450] then built Craig Mound at Spiro while possibly operating a trade system to supply buffalo meat arid hides to the rapidly growing and increasingly protein poor and clothing poor Mississippian populations. . .. to the east. Later, the Mississippians, who were probably ancestral Tunica, retreated back down the Arkansas River to south of Dardenelle, where De Soto encountered them in 1541. The Caddoans then returned to the Spiro area to become the people of the Fort Coffee Phase (A.O. 1450-1500s). This sequence of events is a fascinating reinterpretation of regional culture history, unfortunately it falls flat when confronted by either contemporary theory or the data

The Contingencies of State Formation in Eastern Inner Asia

Three key themes consistently play a role in the study of early state formation in eastern Inner Asia. First, scholars have frequently argued that China exerted a disproportionately strong influence on steppe polities, serving as a source of goods and ideas for neighboring pastoralist societies. Although Chinese states did very significantly influence steppe polities, interactions were complex and highly variable. Rather than being dominated by Chinese states, exchanges and interactions were often on a level of parity or were under the control of the steppe polities. It is frequently argued that the fragility of the pastoralist economy required steppe polities to acquire agricultural products, which in turn fostered a dependency on agricultural societies in the south. New evidence, however, suggests that the traditional distinction between pastoralist and agriculturalist economies may be insufficient to characterize the complex sets of interactions. Second, steppe polities are often described as short-lived entities that succeeded each other in rapid succession. This description deemphasizes the economic and cultural continuity that transcended the rise and fall of individual political entities. The third theme concerns the construction and maintenance of order. How, in other words, did rulers legitimate their power and maintain political and organizational control of populations and territories? Most interpretations argue that steppe polities looked to neighboring states for the cultural knowledge that allowed them to create and maintain order. That knowledge, however, came from multiple sources-especially the internal traditions that linked successive steppe polities. KEYWORDS: state formation, empires, Inner Asia, social theory, power relations

Hybrid and Thin Power Electronics for Electrical Power Networks

A new hybrid diverter design for an On-Load Tap Changer (OLTC) is presented and experimentally validated. The design differs from existing semiconductor-assisted OLTC systems in that the part of the system containing semiconductor devices is connected in a purely shunt con guration to the main current path, resulting in a system that is electrically robust and very low loss. The new design provides zero-current, zero-voltage operation of both diverter switches at all times, eff ectively eliminating arc-induced contact wear. Contact lifetime of over twenty-five million operations is demonstrated. Contact wear rates under the new design are compared experimentally with those under alternative contact protection schemes and are shown to be dramatically reduced. A fast electromechanical switch intended for use under the new hybrid diverter is presented. The low-wear conditions created by the new diverter allows a dramatic reduction in the switch moving mass when compared to that of the standard OLTC, allowing sub-half-cycle actuation times to be achieved. A study of switch topology is made in order to guide the design process. An analysis of a magnetic actuator providing both high actuation and static contact forces is also presented. In a second strand of this thesis, a general method of formulating optimal modulation problems for thin power electronic systems incorporating a buck converter is presented. The method is employs a frequency domain representation of the buck converter where the describing equations are formed into a square matrix relating a set of input harmonics to sets of output harmonics. This allows the interaction between the buck converter and a set of linear filters to be modelled in a systematic way. Two example circuits, the Inverter-Less Active Filter and the Controllable Network Transformer, are used as example problems. The use of general-purpose optimisation software for finding optimal modulation waveforms for these circuits is demonstrated