Efficiency and Technological Change in Health Care Services in Ontario

This paper presents productivity measurement results for hospital services using panel data for Ontario hospitals between 2003 and 2006. The study uses the Malmquist Productivity index (MPI) obtained through the application of Data Envelopment Analysis (DEA) which is decomposed into efficiency change (ECH), i.e., movement towards the best practice frontier and technological change (TCH), i.e., movement of the frontier itself (Färe et al. [12]). The study also uses kernel density estimation techniques for analysis of efficiency distributions of the productivity scores and their components across different types of hospitals (e.g. small /large and rural /urban) and over time. Our results suggest that in addition to average productivity it is important to examine distributions of productivity and of its components which we find differs by hospital type and over time. We find that productivity growth occurred mostly through improvement in technology and in spite of declining efficiency. The results provide useful insight into the underlying mechanisms of observed changes in overall productivity, in technological change and in technical efficiency change in this vital sector of the health care market.

Voltage Stability Analysis: V-Q Power Flow Simulation versus Dynamic Simulation

Several analysis methods are available for long-term voltage stability. The V-Q curve power flow method is widely used by Western Systems Coordinating Council utilities, and has some advantages. Long-term dynamic simulation with proper modeling, however, is clearly the most accurate simulation method. The authors compare the two methods for wintertime voltage stability problems in the Portland, Oregon, USA, load area. Results from the V-Q method can be misleading. The same is true of other power flow program based analysis employing conventional modeling. Results from these power flow methods may be pessimistic, causing overdesign or overly conservative operation

On the kinks and dynamical phase transitions of alpha-helix protein chains

Heuristic insights into a physical picture of Davydov's solitonic model of the one-dimensional protein chain are presented supporting the idea of a non-equilibrium competition between the Davydov phase and a complementary, dynamical- `ferroelectric' phase along the chainComment: small latex file with possible glue problems, just go on !, no figures, small corrections with respect to the published text, follow-up work to cond-mat/9304034 [PRE 47 (June 1993) R3818

Optimizing Traffic Lights in a Cellular Automaton Model for City Traffic

We study the impact of global traffic light control strategies in a recently proposed cellular automaton model for vehicular traffic in city networks. The model combines basic ideas of the Biham-Middleton-Levine model for city traffic and the Nagel-Schreckenberg model for highway traffic. The city network has a simple square lattice geometry. All streets and intersections are treated equally, i.e., there are no dominant streets. Starting from a simple synchronized strategy we show that the capacity of the network strongly depends on the cycle times of the traffic lights. Moreover we point out that the optimal time periods are determined by the geometric characteristics of the network, i.e., the distance between the intersections. In the case of synchronized traffic lights the derivation of the optimal cycle times in the network can be reduced to a simpler problem, the flow optimization of a single street with one traffic light operating as a bottleneck. In order to obtain an enhanced throughput in the model improved global strategies are tested, e.g., green wave and random switching strategies, which lead to surprising results.Comment: 13 pages, 10 figure

What Are the Factors Influence on Construction Safety? A Review

Because of resource constraints, construction safety management is more difficult in underdeveloped nations. The aim of this paper is to explore and identify the key factors affecting construction site safety performance.  The first step in this study was a systematic assessment of 98 papers using a content qualitative approach. From this review, 12 influential factors for safety performance in construction projects were identified. Second, a framework was developed to illustrate the interactions between the identified factors at various project management levels. Furthermore, expert interviews were used to validate the framework. The findings of this study will help project managers better understand how different important safety issues at different construction project hierarchies affect the safety performance of the sites

Counter Chemotactic Flow in Quasi-One-Dimensional Path

Quasi-one-dimensional bidirectional particle flow including the effect of chemotaxis is investigated through a modification of the John-Schadschneider-Chowdhury-Nishinari model. Specifically, we permit multiple lanes to be shared by both directionally traveling particles. The relation between particle density and flux is studied for several evaporation rates of pheromone, and the following results are obtained: i) in the low-particle-density range, the flux is enlarged by pheromone if the pheromone evaporation rate is sufficiently low, ii) in the high particle-density range, the flux is largest at a reasonably high evaporation rate and, iii) if the evaporation rate is at the level intermediate between the above two cases, the flux is kept small in the entire range of particle densities. The mechanism of these behaviors is investigated by observing the spatial-temporal evolution of particles and the average cluster size in the system.Comment: 4 pages, 9 figure

On marine liability portfolio modeling

Marine is the oldest type of insurance coverage. Nevertheless, unlike cargo and hull covers, marine liability is a rather young line of business with claims that can have very heavy and long tails. For reinsurers, the accumulation of losses from an event insured by various Protection and Indemnity (P&I) Clubs is an additional source for very large claims in the portfolio. In this paper we first describe some recent developments of the marine liability market and then statistically analyze a data set of large losses for this line of business in a detailed manner both in terms of frequency and severity, including censoring techniques and tests for stationarity over time. We further formalize and examine an optimization problem that occurs for reinsurers participating in XL on XL coverages in this line of business and give illustrations of its solution

Photolithography Process Characterization and 3D Simulation Using Track-Mounted Development Rate Monitor Data

A track-mounted, in-situ Dissolution Rate Monitor (DRM) is used to study the impact of exposure variations on g-line, i-line and DUV positive chemically-amplified resists. In the i-line case, a comparative study between constant spray and a spray/puddle process was undertaken. In all cases, modeling parameters were extracted from the track-mounted DRM data and entered into 2D and 3D simulators using an experimentally-generated Development Rate vs. PAC concentration table. Simulated profiles were compared with actual SEM cross-sections. Whenever possible, DRM traces were used to analyze standing waves, surface inhibition effects and quantify resist performance by calculating contrast. For the g-line case, the impact of PEB temperature upon the standing wave effects, as quantified by the in-situ DRM data, was studied

Surface critical behavior of random systems at the ordinary transition

We calculate the surface critical exponents of the ordinary transition occuring in semi-infinite, quenched dilute Ising-like systems. This is done by applying the field theoretic approach directly in d=3 dimensions up to the two-loop approximation, as well as in $d=4-\epsilon$ dimensions. At $d=4-\epsilon$ we extend, up to the next-to-leading order, the previous first-order results of the $\sqrt{\epsilon}$ expansion by Ohno and Okabe [Phys.Rev.B 46, 5917 (1992)]. In both cases the numerical estimates for surface exponents are computed using Pade approximants extrapolating the perturbation theory expansions. The obtained results indicate that the critical behavior of semi-infinite systems with quenched bulk disorder is characterized by the new set of surface critical exponents.Comment: 11 pages, 11 figure