Computationally Efficient Trajectory Optimization for Linear Control Systems with Input and State Constraints

This paper presents a trajectory generation method that optimizes a quadratic cost functional with respect to linear system dynamics and to linear input and state constraints. The method is based on continuous-time flatness-based trajectory generation, and the outputs are parameterized using a polynomial basis. A method to parameterize the constraints is introduced using a result on polynomial nonpositivity. The resulting parameterized problem remains linear-quadratic and can be solved using quadratic programming. The problem can be further simplified to a linear programming problem by linearization around the unconstrained optimum. The method promises to be computationally efficient for constrained systems with a high optimization horizon. As application, a predictive torque controller for a permanent magnet synchronous motor which is based on real-time optimization is presented.Comment: Proceedings of the American Control Conference (ACC), pp. 1904-1909, San Francisco, USA, June 29 - July 1, 201

Recession and the Employment of Demographic Groups

macroeconomics, Recession, Demographic

Regional Inequality and Industrial Structures in Pre-War Japan: An Analysis Based on New Prefectural GDP Estimates

Studies comparing regional income in Japan before and after World War II have frequently drawn a picture of radical change from an economy characterized by large regional disparities to one characterized by small regional disparities. This paper comes to a very different conclusion. Based on estimates of prefecture-level value added for five benchmark years from 1890 to 1940 (a detailed description of our estimation methodology is provided), we examine trends in the gap of economic development between prefectures during the pre-war period and find that this gap was much smaller than claimed in preceding studies and, in fact, not much greater than during the post-war period. Observing, moreover, a decline in inter-prefectural differences in terms of per-capita gross value added during the pre-war period, we conduct a factor analysis and find that a major reason for this decline was a decline in inter-prefectural differences in same-industry labor productivity. Thus, the picture of modern Japan's economic development presented here is very different from the one painted by preceding studies.

Raman spectroscopy and field emission measurements on catalytically grown carbon nanotubes

We used microcontact printing to pattern a silicon surface with an iron-containing catalytic solution. Multi-wall carbon nanotubes were subsequently grown on the patterned areas by chemical vapor deposition at temperatures between 650 and 1000C. We demonstrate that the diameter of the catalytically grown multi-wall nanotubes increases with the deposition temperature. Raman spectroscopy has been used to investigate the crystalline character of the obtained structures and it is found that the fraction of the nano-crystalline shell increases with the temperatures. The measurement of the field emission properties shows a correlation between the tube diameter and the emission field values.Comment: 6 pages, 6 figures, 1 tabl

Digitization of multistep organic synthesis in reactionware for on-demand pharmaceuticals

Chemical manufacturing is often done at large facilities that require a sizable capital investment and then produce key compounds for a finite period. We present an approach to the manufacturing of fine chemicals and pharmaceuticals in a self-contained plastic reactionware device. The device was designed and constructed by using a chemical to computer-automated design (ChemCAD) approach that enables the translation of traditional bench-scale synthesis into a platform-independent digital code. This in turn guides production of a three-dimensional printed device that encloses the entire synthetic route internally via simple operations. We demonstrate the approach for the γ-aminobutyric acid receptor agonist, (±)-baclofen, establishing a concept that paves the way for the local manufacture of drugs outside of specialist facilities

Global Burden Related to Nitrous Oxide Exposure in Medical and Recreational Settings: A Systematic Review and Individual Patient Data Meta-Analysis.

The risk of adverse effects of nitrous oxide (N2O) exposure is insufficiently recognized despite its widespread use. These effects are mainly reported through case reports. We conducted an individual patient data meta-analysis to assess the prevalence of clinical, laboratory, and magnetic resonance findings in association with N2O exposure in medical and recreational settings. We calculated the pooled estimates for the studied outcomes and assessed the potential bias related to population stratification using principal component analysis. Eighty-five publications met the inclusion criteria and reported on 100 patients with a median age of 27 years and 57% of recreational users. The most frequent outcomes were subacute combined degeneration (28%), myelopathy (26%), and generalized demyelinating polyneuropathy (23%). A T2 signal hyperintensity in the spinal cord was reported in 68% (57.2-78.8%) of patients. The most frequent clinical manifestations included paresthesia (80%; 72.0-88.0%), unsteady gait (58%; 48.2-67.8%), and weakness (43%; 33.1-52.9%). At least one hematological abnormality was retrieved in 71.7% (59.9-83.4%) of patients. Most patients had vitamin B12 deficiency: vitamin B12 <150 pmol/L (70.7%; 60.7-80.8%), homocysteine >15 µmol/L (90.3%; 79.3-100%), and methylmalonic acid >0.4 µmol/L (93.8%; 80.4-100%). Consistently, 85% of patients exhibited a possibly or probably deficient vitamin B12 status according to the cB12 scoring system. N2O can produce severe outcomes, with neurological or hematological disorders in almost all published cases. More than half of them are reported in the setting of recreational use. The N2O-related burden is dominated by vitamin B12 deficiency. This highlights the need to evaluate whether correcting B12 deficiency would prevent N2O-related toxicity, particularly in countries with a high prevalence of B12 deficiency