Building the Infrastructure: The Effects of Role Identification Behaviors on Team Cognition Development and Performance

The primary purpose of this study was to extend theory and research regarding the emergence of mental models and transactive memory in teams. Utilizing Kozlowski et al.’s (1999) model of team compilation, we examine the effect of role identification behaviors and argue that such behaviors represent the initial building blocks of team cognition during the role compilation phase of team development. We then hypothesized that team mental models and transactive memory would convey the effects of these behaviors onto team performance in the team compilation phase of development. Results from 60 teams working on a command and control simulation supported our hypotheses

Formulation and Application of an Economic Model Predictive Control Scheme for Thermostats

Within the last ten years, growing pressure to reduce energy consumption of buildings has led to an increased focus on the development and deployment of advanced control strategies. Heating, Ventilation, and Air-Conditioning (HVAC) constitutes the majority of the energy consumption of buildings. Model predictive control (MPC) has gained significant attention in HVAC control as it computes the control inputs for a given system by iteratively solving an optimal control problem on-line. The problem formulation accounts for the system operating objective and constraints. Several application studies of MPC applied to buildings have been reported in the literature. These studies have demonstrated the benefits of the application of MPC schemes to buildings. However, one theme that appears in some of the literature is the lamentation on the difficulty to apply MPC broadly to buildings. This is a challenging problem because the MPC system design needs to include a robust and broadly applicable system identification methodology to effectively address this problem. Moreover, in many building applications, the desired sensors measuring key variables are not available (e.g., a heat disturbance load and power consumption measurements are usually not available for residential zones controlled by a thermostat). In this work, an economic MPC scheme is developed to manipulate the temperature setpoint of a zone controlled by a thermostat. The MPC scheme is equipped with an economically-oriented objective that includes a system identification procedure, a state estimator, and a control problem formulation. The economically-oriented MPC seeks to minimize the utility bill by manipulating the setpoint to leverage the building mass as thermal energy storage while maintaining the zone temperature setpoint within a comfortable range. Given the lack of a power or HVAC load measurement in a typical thermostat, the HVAC load is approximated by a filtered version of the thermostat stage commands, which provides a normalized time-average version of the HVAC load. All the components of the resulting MPC scheme are designed in a manner to address general applicability of the resulting MPC. Simulation results are presented to demonstrate the effectiveness of the strategy

Health outcomes in patients using no-prescription online pharmacies to purchase prescription drugs

BACKGROUND: Many prescription drugs are freely available for purchase on the Internet without a legitimate prescription from a physician. OBJECTIVE: This study focused on the motivations for using no-prescription online pharmacies (NPOPs) to purchase prescription drugs rather than using the traditional doctor-patient-pharmacy model. We also studied whether users of NPOP-purchased drugs had poorer health outcomes than those who obtain the same drug through legitimate health care channels. METHODS: We selected tramadol as a representative drug to address our objective because it is widely prescribed as an unscheduled opioid analgesic and can easily be purchased from NPOPs. Using search engine marketing (SEM), we placed advertisements on search result pages stemming from the keyword “tramadol” and related terms and phrases. Participants, who either used the traditional doctor-patient-pharmacy model to obtain tramadol (traditional users, n=349) or purchased it on the Web without a prescription from their local doctor (ie, nontraditional users, n=96), were then asked to complete an online survey. RESULTS: Respondents in both groups were primarily white, female, and in their mid-forties (nontraditional users) to upper forties (traditional users). Nearly all nontraditional users indicated that their tramadol use was motivated by a need to treat pain (95%, 91/96) that they perceived was not managed appropriately through legitimate health care channels. A majority of nontraditional users (55%, 41/75) indicated they used NPOPs because they did not have access to sufficient doses of tramadol to relieve pain. In addition, 29% (22/75) of nontraditional users indicated that the NPOPs were a far cheaper alternative than seeing a physician, paying for an office visit, and filling a prescription at a local pharmacy, which is often at noninsured rates for those who lack medical insurance (37%, 35/96, of NPOP users). The remainder of participants (16%, 12/96) cited other motivations (eg, anonymity) for using NPOPs. In terms of health outcomes, nontraditional users experienced a significantly (P<.01) greater number and severity of adverse events, including life-threatening seizures: 7% (7/96) of nontraditional users reported seizures, while none of the traditional users reported seizures. CONCLUSIONS: Although online pharmacies can offer distinct advantages in terms of convenience and cost, users of these “rogue” pharmacies that offer drugs with no prescription or doctor supervision do so at great risk to their health, as evidenced by much higher rates of adverse events. The most logical explanation for these findings is that the lack of physician oversight of dosage schedules, contraindicated conditions, and concomitant medications, were responsible for the increased intensity and frequency of adverse events in the nontraditional users. Although we only examined tramadol, it is logical to postulate that similar results would be observed with dozens of equally accessible prescription drugs. As such, the geometric growth in the use of online pharmacies around the world should prompt intense medical and regulatory discussion about their role in the provision of medical care

Are There Hints of Light Stops in Recent Higgs Search Results?

The recent discovery at the LHC by the CMS and ATLAS collaborations of the Higgs boson presents, at long last, direct probes of the mechanism for electroweak symmetry breaking. While it is clear from the observations that the new particle plays some role in this process, it is not yet apparent whether the couplings and widths of the observed particle match those predicted by the Standard Model. In this paper, we perform a global fit of the Higgs results from the LHC and Tevatron. While these results could be subject to as-yet-unknown systematics, we find that the data are significantly better fit by a Higgs with a suppressed width to gluon-gluon and an enhanced width to gamma gamma, relative to the predictions of the Standard Model. After considering a variety of new physics scenarios which could potenially modify these widths, we find that the most promising possibility is the addition of a new colored, charged particle, with a large coupling to the Higgs. Of particular interest is a light, and highly mixed, stop, which we show can provide the required alterations to the combination of gg and gamma gamma widths.Comment: 6 pages, 5 figure

System Identification for Model Predictive Control of Building Region Temperature

Model predictive control (MPC) is a promising technology for energy cost optimization of buildings because it provides a natural framework for optimally controlling such systems by computing control actions that minimize the energy cost while meeting constraints. In our previous work, we developed a cascaded MPC framework capable of minimizing the energy cost of building zone temperature control applications. The outer loop MPC computes power set-points to minimize the energy cost while ensuring that the zone temperature is maintained within its comfort constraints. The inner loop MPC receives the power set-points from the outer loop MPC and manipulates the zone temperature set-point to ensure that the zone power consumption tracks the power set-points computed by the outer layer MPC. Since both MPCs require a predictive model, a modeling framework and system identification (SI) methodology must be developed that is capable of accurately predicting the energy usage and zone temperature for a diverse range of building zones. In this work, two grey-box models for the outer and inner loop MPCs are developed and parameterized. The model parameters are fit to input-output data for a particular zone application so that the resulting model accurately predicts the behavior of the zone. State and disturbance estimation, which is required by the MPCs, is performed via a Kalman filter with a steady-state Kalman gain. The model parameters and Kalman gains of each grey-box model are updated in a sequential fashion. The significant disturbances affecting the zone temperature (e.g., outside temperature and occupancy) may typically be considered as a slowly varying disturbance (with respect to the control time-scale). To prevent steady-state offset in the identified model caused by the slowly time-varying disturbance, a high-pass filter is applied to the input-output data to filter out the effect of the disturbance. The model parameters are subsequently computed from the filtered input-output data without the Kalman filter applied. The Kalman gain is also adjusted as the model parameters are updated to ensure stability of the resulting observer and for optimal estimation. After the model parameters are computed, the steady-state Kalman gain matrix is parameterized and the parameters are updated using the prediction error method with the unfiltered input-output data and the updated model parameters. The Kalman gain update methodology is advantageous because it avoids the need to estimate the noise statistics. Stability of the observer is verified after the parameters are updated. If the updated parameters result in an unstable observer, the update is rejected and the previous parameters are retained. Additionally, since a standard quadratic cost function that penalizes the squared prediction error is sensitive to data outliers in the prediction error method, a piecewise defined cost function is employed to reduce its sensitivity to outliers and to improve the robustness of the SI methodology. The cost function penalizes the squared prediction error when the error is within certain thresholds. When the error is outside the thresholds, the cost function evaluates to a constant. The SI algorithm is applied to a building zone to assess the approach

Economic Model Predictive Control for Variable Refrigerant Systems

Variable refrigerant (VRF) systems are in a unique position to be combined with economic model predictive control (MPC) in order to reap significant benefits. In buildings with a variable utility price, it is feasible to use the building mass to shift a portion of the building heating, ventilation, and air conditioning (HVAC) load from the high priced (peak) period to the low priced (off-peak) period. It is also feasible for further savings to be visualized through a reduction of the monthly demand charge. By employing the building mass as an element to store thermal energy, one can see a significant reduction in utility costs. The MPC algorithm can accomplish this by using the building mass to store and release heat at the appropriate time to reduce HVAC usage during the peak utility price periods. This is accomplished through MPC of the indoor air temperature within the acceptable temperature set point limits. With proper, linear models, a linear programming (LP) algorithm can be employed to perform the economic optimization over the future time horizon. Savings in commercial buildings estimate HVAC cost savings from --% to --% annually