Control of sideslip and yaw rate in 4-wheel steering car using partial decoupling and individual channel design

This paper presents a new steering control structure for cars equipped with 4-wheel steering. This control structure is based on a simplified linear model of the lateral dynamics of such cars and aims to decouple the control of sideslip from the control of yaw rate. The control design is based on a linear multivariable plant which incorporates the model of the lateral dynamics mentioned above and whose inputs are linear combinations of the front and rear steering angles. The plant also contains a cross-feedback element. The matrix transfer function of the resulting plant is upper-triangular (partially decoupled). The MIMO design problem can then be recast as two SISO design problems using channel decomposition according to the Individual Channel Design (ICD) paradigm. The proposed control structure has been applied to design sideslip and yaw rate controllers using a more accurate model of the lateral dynamics of 4-wheel steering cars. This model incorporates the tyre force dynamics and the steering actuators. Simulations are used to illustrate the performance and robustness of the designed controllers

Sovereign default and monetary policy tradeoffs

The paper is organized around the following question: when the economy moves from a debt-GDP level where the probability of default is nil to a higher level—the “fiscal limit”—where the default probability is non-negligible, how do the effects of routine monetary operations designed to achieve macroeconomic stabilization change? We find that the specification of the monetary policy rule plays a critical role. Consider a central bank that targets the risky rate. When the economy is near its fiscal limit, a transitory monetary policy contraction leads to a sustained rise in inflation, even though monetary policy actively targets inflation and fiscal policy passively adjusts taxes to stabilize debt. If the central bank targets the riskfree rate, on the other hand, the same transitory monetary contraction keeps inflation under control but leads output to contract for a prolonged period of time. The comparison shows that sovereign default risk puts into sharp relief the tradeoff between inflation and output stabilization

Non-minimally coupled multi-scalar black holes

We study the static, spherically symmetric black hole solutions for a non-minimally coupled multi-scalar theory. We find numerical solutions for values of the scalar fields when a certain constraint on the maximal charge is satisfied. Beyond this constraint no black hole solutions exist. This constraint therefore corresponds to extremal solutions, however, this does not match the \kappa = 0 constraint which typically indicates extremal solutions in other models. This implies that the set of extremal solutions have non-zero, finite and varying surface gravity. These solutions also violate the no-hair theorems for N>1 scalar fields and have previously been proven to be linearly stable.Comment: 6 pages, 4 figure

Uncertain Fiscal Consolidations

The paper explores the macroeconomic consequences of fiscal consolidations whose timing and composition are uncertain. Drawing on the evidence in Alesina and Ardagna (2010), we emphasize whether or not the fiscal consolidation is driven by tax rises or expenditure cuts. We find that the composition of the fiscal consolidation, its duration, the monetary policy stance, the level of government debt and expectations over the likelihood and composition of fiscal consolidations all matter in determining the extent to which a given consolidation is expansionary and/or successful in stabilizing government debt.government debt, budget reform, monetary-fiscal policy interactions

Gravitational energy as dark energy: Concordance of cosmological tests

We provide preliminary quantitative evidence that a new solution to averaging the observed inhomogeneous structure of matter in the universe [gr-qc/0702082, arxiv:0709.0732], may lead to an observationally viable cosmology without exotic dark energy. We find parameters which simultaneously satisfy three independent tests: the match to the angular scale of the sound horizon detected in the cosmic microwave background anisotropy spectrum; the effective comoving baryon acoustic oscillation scale detected in galaxy clustering statistics; and type Ia supernova luminosity distances. Independently of the supernova data, concordance is obtained for a value of the Hubble constant which agrees with the measurement of the Hubble Key team of Sandage et al [astro-ph/0603647]. Best-fit parameters include a global average Hubble constant H_0 = 61.7 (+1.2/-1.1) km/s/Mpc, a present epoch void volume fraction of f_{v0} = 0.76 (+0.12/-0.09), and an age of the universe of 14.7 (+0.7/-0.5) billion years as measured by observers in galaxies. The mass ratio of non-baryonic dark matter to baryonic matter is 3.1 (+2.5/-2.4), computed with a baryon-to-photon ratio that concords with primordial lithium abundances.Comment: 4 pages, 2 figures; v2 improved statistics, references added, to appear in ApJ Letter

Uncertain Fiscal Consolidations

The paper explores the macroeconomic consequences of fiscal consolidations whose timing and composition are uncertain. Drawing on the evidence in Alesina and Ardagna (2010), we emphasize whether or not the fiscal consolidation is driven by tax rises or expenditure cuts. We find that the composition of the fiscal consolidation, its duration, the monetary policy stance, the level of government debt and expectations over the likelihood and composition of fiscal consolidations all matter in determining the extent to which a given consolidation is expansionary and/or successful in stabilizing government debt.

The Limits of the Effects of Machiavellianism on Bargaining Success in Triads

Understanding the processes of communication during mixed-motive bargaining in coalition depends to a great extent upon comprehension of the variables which affect it. Certainly one of the most important variables of such communication is the influence of personality effect upon the bargaining outcomes. One personality variable, Machiavellianism, is strongly related to manipulative behavior. This thesis examines both the effects of Machiavellianism on bargaining success in face-to-face triads, and explores the limits of those effects relative to task orientation and personality type disclosure. It was found that Machiavellians are more able bargainers only so long as the nature and identity of their personality type is not revealed to their opponents. Machiavellian bargaining tactics, power strategies, styles of communication, and a variety of factors related to bargaining success are analyzed and a theory of ordering these results in terms of conflict resolution is discussed

Single-molecule Studies Of p53 Sliding Along DNA

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Recursive Use of GPR, Excavation, and Historical Maps at Gore Place, Waltham, Massachusetts

Gore Place is the early 19th-century house and estate of Massachusetts governor Christopher Gore and his wife Rebecca. The Gores were active in scientific agriculture and cultivated grains, fruits, and vegetables on the property. As part of the landscape restoration, the Gore Place Society wished to know the exact location and preservation status of Gore’s stable and greenhouse. To determine these, we recursively combined historic map georeferencing, ground penetrating radar (GPR) survey, and excavation. We used an initial GPR survey to guide our excavation, then using the GPR-slice images and data from the excavations, a series of historical maps were re-georeferenced, allowing for much better interpretation of the GPR-slice images. Interpreting GPR, excavation, and documentary data in this integrated, sequential package yields more information with less excavation than traditional methods

Archaeological Site Examination of the Field East of the Grapery/Greenhouse, Drive Circle, Straight Walk, and South Lawn at Gore Place, Waltham, Massachusetts

A landscape restoration plan for the 45-acre historic estate of Massachusetts governor and United States senator, Christopher Gore and his wife Rebecca, recommended archaeological investigations to identify the location, character, and integrity of Gore-period features that could potentially be included in restoration efforts. Investigations began in 2004, focusing on better known landscape elements including the carriage drive, carriage house foundation, greenhouse, vegetable and flower gardens, and the site of the grapery/fruitwall (Smith and Dubell 2006). The 2008 investigations focused on the new site of the carriage house (reported under separate cover) and on lesser known elements of the estate that functioned in the daily running of Gore’s farm. Transects of staggered shovel test pits at 5, 10 and 20 meter intervals, along with 1×1 m excavation units and trenches, were employed in the archaeological site examination. Investigation of the drive circle north of the mansion showed the centrally-located well to have a wide builder’s trench of large cobblestones covered at the ground surface by a hard-packed layer of silty sand with gravel and clay, potentially to prevent contaminants in the immediate vicinity from entering the water. Identified by subsurface testing and ground penetrating radar was a well access walk that joined a straight-edged carriage drive south of the well. Also revealed was a possible square fieldstone feature that surrounds the well. The bedding of Gore’s historically documented straight walk east of the library was also found. A possible landscape feature of unknown form or function was found at the east terminus of the walk, and the walk’s eastern extension was determined to have been removed in the 1930s during mining of topsoil. Testing of the field east of the grapery identified additional boundaries of the 1930s soil removal and an area measuring approximately 60 × 100 m that is not archaeologically sensitive that is suitable for planting crops to interpret Gore’s agricultural use of the property. Examination of the south lawn revealed much of the area to have been plowed in the past and to have been subjected to fertilizing during the Gore period. A number of Gore-period and non Gore-period features were identified, including two dry wells, drainage pipes, post holes, buried fieldstones of unknown association, a deposit of reddened soil and stones of unknown function, golfing features associated with the use of the property by the Waltham Country Club during the 1920s, and a possible cellar or cesspool filled with Gore-period masonry from late 19th-century cellar and chimney alterations. Investigation of a known cistern revealed similar surface treatment to the drive circle well. Results of the south lawn work also identified an area on the flat, central section of the lawn that is not archaeologically sensitive and can be used for interpretative crop cultivation. An EM-31 conductivity meter survey identified a zone of the south lawn that appears to be the site of numerous anomalies, possibly related to the house’s heating, cooling, or water systems. Recommendations specific to each area consist of examining the square feature surrounding the well in the drive circle and determining the nature of drive bedding that adjoins the well access walk, exploring the east end of the straight walk to determine the nature of the feature at that location, further investigating the south lawn cellar or cesspool feature to determine its function and age, and testing several other south lawn features to determine age and function