Enhanced tracking and recognition of moving objects by reasoning about spatio-temporal continuity.

A framework for the logical and statistical analysis and annotation of dynamic scenes containing occlusion and other uncertainties is presented. This framework consists of three elements; an object tracker module, an object recognition/classification module and a logical consistency, ambiguity and error reasoning engine. The principle behind the object tracker and object recognition modules is to reduce error by increasing ambiguity (by merging objects in close proximity and presenting multiple hypotheses). The reasoning engine deals with error, ambiguity and occlusion in a unified framework to produce a hypothesis that satisfies fundamental constraints on the spatio-temporal continuity of objects. Our algorithm finds a globally consistent model of an extended video sequence that is maximally supported by a voting function based on the output of a statistical classifier. The system results in an annotation that is significantly more accurate than what would be obtained by frame-by-frame evaluation of the classifier output. The framework has been implemented and applied successfully to the analysis of team sports with a single camera. Key words: Visua

Alcohol Fueled Heavy Duty Vehicles Using Clean, High Efficiency Engines

Work sponsored by the John and Jane Bradley gift to the MIT Energy Initiative. Non-petroleum based liquid fuels are essential for reducing oil dependence and greenhouse gas generation. Increased substitution of alcohol fuel for petroleum based fuels could be achieved by 1) use in high efficiency spark ignition engines that are employed for heavy duty as well as light duty operation and 2) use of methanol as well as ethanol. Methanol is the liquid fuel that is most efficiently produced from thermo-chemical gasification of coal, natural gas, waste or biomass. Ethanol can also be produced by this process but at lower efficiency and higher cost. Coal derived methanol is in limited initial use as a transportation fuel in China. Methanol could potentially be produced from natural gas at an economically competitive fuel costs, and with essentially the same greenhouse gas impact as gasoline. Waste derived methanol could also be an affordable low carbon fuel. In this paper we describe modeling studies of alcohol fuel operation in highly turbocharged direct injection spark ignition engines operated at high compression ratio. The studies suggest that these engines could be a

Effective Octane and Efficiency Advantages of Direct Injection Alcohol Engines

Ethanol is receiving great interest as an alternative fuel. Methanol is another alcohol fuel that could serve as a replacement for gasoline. Although it is currently receiving much less attention, it has the potential to play an important role. Like ethanol, methanol also has the advantage of being a liquid fuel and it can be produced from gasification of a variety of feedstocks using well established thermal chemical technology. These feedstocks include coal, natural gas, biomass and various types of waste. This paper discusses the high effective octane number and efficiency advantages of methanol and ethanol when used in direct injection engines. Octane number represents the resistance of a spark ignition engine to knock (unwanted detonation which can damage the engine). The high intrinsic octane numbers of ethanol and methanol are well known. However, a much greater effective octane number can be effectively realized through the knock resistance provided by the high level of vaporization cooling that occurs when methanol or ethanol is directly injected into the engine cylinders. A computational model is used in this paper to determine the knock resistance and effective octane number of these alcohol fuels when they are directly injected. The model indicates that the effective octane numbers are around 160 for ethanol and 180 for methanol. The high compression ratio, high degree of turbocharging and aggressive engine downsizing enabled by the high effective octane number of methanol could provide an efficiency gain of 30 –35 % (for combined city-highway driving) relative to conventional port fueled gasoline engines. An additional gain of around 10 % can be obtained by using reforming of methanol to enable ultra lean operation at low loads. The combination of these gains could thus potentially provide an efficiency gain of 40–45 % for direct injection methanol engines. This efficiency gain is significantly greater than the typical 25–30 % gain of turbocharged diesel engines. 3I

Effect of Compression Ratio and Manifold Pressure on Ethanol Utilizationin Gasoline/Ethanol Engines

The model developed previously for evaluating the impact of direct ethanol injection on the avoidance of knock in spark ignition engines is used to evaluate the trends of changes in compression ratio and variation in the inlet pressure. The ethanol fraction requirements through the engine map is calculated using detailed chemical kinetics model, and a vehicle simulation is used to determine the required ethanol for multiple driving cycles. The operation of spark ignition engines is severely constrained by the occurrence of knock, the uncontrolled ignition of a fraction of the air fuel mixture during in the cylinder [1]. The effect limits the maximum compression ratio and inlet manifold pressure in the cylinder. The knock limit prevents design of an engine that uses the features that hav