448 research outputs found

    Clinical Insights about Mental Difference

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    Self-actualization is sought by all people. Experience with mental difference, both as a patient and as a staff member in a mental hospital leads to a greater understanding of the meaning and nature of this difference. It arises from variations in biographical experience, social interactions, personal frame and self-choice. Providing the mentally different with the responsibility of at least limited choice empowers them while affirming their human dignity and worth

    Optical scattering for security applications

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    Laser Surface Authentication (LSA) has emerged in recent years as a potentially disruptive tracking and authentication technology. A strong need for such a solution in a variety of industries drove the implementation of the technology faster than the scientific understanding could keep up. The drive to miniaturise and simplify, the need to be robust against real-world problems like damage and misuse, and not least, intellectual curiosity, make it clear that a firmer scientific footing is important as the technology matures. Existing scattering and biometric work are reviewed, and LSA is introduced as a technology. The results of field-work highlight the restrictions which are encountered when the technology is applied. Analysis of the datasets collected in the trial provide, first, an indication of the performance of LSA under real-world conditions and, second, insight into the potential shortcomings of the technique. Using the particulars of the current sensor’s geometry, the LSA signal is characterised. Measurements are made of the decorrelation of the signature with linear and rotational offsets, and it is concluded that while surface microstructure has a strong impact on the rate of decorrelation, this dependency is not driven by the surface’s feature size. A new series of experiments examine that same decorrelation for interference effects with different illumination conditions, and conclude that laser speckle is not an adequate explanation for the phenomenon. The results of this experimental work inform a mathematical description of LSA based on a combination of existing bi-static scattering models used in physics and ray-tracing, which is implemented numerically. The results of the model are found to be a good fit to experimental work, and new predictions are made about LSA

    Homotopifikspunkter og Nielsen-teori

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    Et fikspunkt for en selvavbildning f: X -> X er et punkt x som oppfyller likningen f(x) = x. Mengden av fikspunkter kalles Fix(f). I fikspunktteori studeres egenskapene til Fix(f) for forskjellige f og X. Man deler mengden av fikspunker for en selvavbildning inn i ekvivalensklasser, såkalte fikspunktklasser. I Nielsen-teori studeres tallene R(f) (Reidemeister-tallet), N(f) (Nielsen-tallet) og L(f) (Lefschetz-tallet). R(f) er det totale antallet fikspunktklasser, mens N(f) er antallet essensielle fikspunktklasser, de som ikke forsvinner under homotopi. Disse tallene er alle homotopiinvariante. Når X er en mangfoldighet kan vi gjøre en videre generalisering av Reidemeister-tallet, og se på Reidemeister-trasen, ikke et tall, men et element i en bestemt fri abelsk gruppe. Målet med oppgaven er å vise en formel for Reidemeister-trasen og å vise homotopiinvarians av denne ved hjelp av formelen. Oppgaven avsluttes med en utvidelse av formelen til å gjelde for visse endelige CW-komplekser

    Multi-variable Extremum Seeking Control for Mini-split Air-conditioning System

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    In this study, a multi-variable extremum seeking control (ESC) scheme is proposed for a variable-speed mini-split air-conditioning system. The control inputs are the evaporator and condenser fan speeds, respectively, while the total power consumption is used as the feedback. As accurate model is hard and expensive to obtain for the AC system of interest in real time, nearly model-free self-optimizing control methods such as ESC is considered a more feasible solution to practical deployment. Recent development in ESC, and especially the Newton based multi-variable ESC method with online Hessian estimation provides the capability for real-time decoupling among the input channels (Ghaffari et al. 2012). Different from gradient based multi-variable ESC method, the Newton based multi-variable ESC provides uniform convergence characteristics for all the control inputs. Therefore, the Newton based multi-variable ESC is suitable for multi-input real-time optimization, especially for the case with large gain variation and coupling for different control input channels. An experimental setup is developed with a 9000 BTU variable-speed mini-split AC system (Mitsubishi MSZ-GE09NA & MUY-GE09NA). A 2000 Watts electrical heater works as the heat load. The indoor unit of the mini-split system and the heater are installed in a 4’x8’x6’ insulated chamber. A Watt Node Pulse WNB-3D-240-P power meter is utilized to measure the power consumption of the mini-split system. To achieve the speed control of the evaporator fan motor and condenser fan, a TMS320F28035 based customized motor controller is used. Three RTD temperature sensors are deployed to measure the indoor temperature, the outdoor temperature and the condenser coil temperature, respectively. The data acquisition and control algorithms are implemented on a National Instruments CompactRIO platform. During the system operation, the CompactRIO reads the power consumption sent from the power meter, which will be fed into the ESC control algorithm to get the speed reference for both the evaporator fan and the condenser fan. Then, the speed reference will be applied to the motor controllers for each motor. Meanwhile, some other measurements such as indoor temperature, outdoor temperature, the speed feedback for both the motors, etc. are also monitored by the CompactRIO. The experimental study is planned to include three scenarios of ESC implementation: 1) single-input ESC with evaporator fan speed input only; 2) single-input ESC with condenser fan speed input only; and 3) multi-variable ESC with both evaporator and condenser fan speed inputs. Experimental study has performed for the first scenario. Under the ambient temperature of 75F and indoor room temperature set-point of 68F, the ESC control results in an energy saving of 20%. The work under way includes the other two scenarios and in particular the multi-variable ESC. More experiments will be performed under various weather conditions

    Geneva Grad Students Honored

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    Modelica Based Dynamic Modeling of Water-Cooled Centrifugal Chillers

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    Ascospore release by Venturia inaequalis during periods of extended daylight and low temperature at Nordic latitudes

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    Darkness suppresses ascospore release in Venturia inaequalis, but the impact of light levels during the extended twilight and dusk that typify Nordic spring conditions is poorly understood. Volumetric spore traps were operated at two different locations in Norway over several years. During the season of asocspore release (approximately 1 April to 30 June), on 25 occasions when rain started during night (after 23:00h and before 04:00h) and leaves remained wet until at least midnight the following day, the cumulative percentage of spores trapped at sunrise did not exceed 1%, irrespective of temperature. Three hours after sunrise, cumulative ascospore release reached 0.8%, 3.0%, and 8.1% at temperatures of 0 to 5°C, 5 to 10°C, and >10°C, respectively, and 50% release occurred at 11, 9, and 8h after sunrise. Additional field and laboratory studies indicated that the protracted dawn and dusk of Nordic latitudes, either alone or in combination with low temperatures, does not substantially alter previously reported patterns of ascospore releas

    Experimental Study on Extremum Seeking Control for Efficient Operation of Air-side Economizer

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    The air-side economizers are a major class of energy-saving devices for ventilation and air conditioning systems by taking advantage of outdoor air during cool or cold weather. Typical rule based control cannot justify energy optimal operation, while model based optimization of air-side economizer operation depends on the accurate knowledge of system model and enthalpy sensing of the ambient and return-air. Such optimal operation is hard to achieve in practice due to inaccurate model and degradation/failure of temperature and relative humidity (RH) sensors. As pointed out by Seem and House (2010), under certain indoor/outdoor air conditions, there exists a convex map between damper position and energy consumption of an air handling unit (AHU), which implies an optimal damper opening minimizing the cooling-coil load. Such convexity guarantees the use of gradient-search type of real-time optimization methods. An Extremum Seeking Control (ESC) was proposed by Li et al. (2009), where the chilled water flow rate of the cooling coil (equivalently the energy consumption) is minimized by tuning the damper opening. The proposed framework was validated with a Modelica based dynamic simulation model of an air-side economizer. This study is conducted to perform experimental evaluation of the ESC control of air-side economizer. The experimental setup is anchored on a Lennox XC25 variable-speed air conditioner. The Lennox, CBX40UHV indoor air handler unit is equipped with duct work to form an air-side economizer, connected to a foam based 16\u27X8\u27X8\u27 test chamber. The Lasko 751320 electrical heaters are used as heat source. The Honeywell HCM-890 humidifiers and Soleus Air SG-DEH-70EIP-6 dehumidifiers are used to regulate the indoor air humidity. A National Instruments CompactRIO-9024 platform is used for data acquisition and control. Major measurements include temperature, relative humidity (RH) and power consumption. A Watt Node Pulse WNB-3D-240-P electric power meter is used for power measurement. The Omega P-L-1/10-1/8-6-0-T-3 temperature sensors and Veris Industries HN3XVSX RH sensors are installed to monitor the indoor and outdoor air conditions. The Omega HHT13 speed sensors are used to measure fan speeds, while Fluke 80i-110s current sensors are used to measure the compressor motor current. The ESC controller is implemented with the damper opening as input and the total power consumption as feedback. Two experiments have been performed under different indoor/outdoor air conditions. The first experiment was performed under outdoor air temperature 23°C and RH 65%, a heat load of 6000 W and indoor temperature setpoint 28°C. The ESC turned on the outdoor damper 100% automatically to allow maximal outdoor air resulting in indoor RH 50%. The total power consumption was reduced from 540 W to 450 W with an energy saving of 16.67%. The second experiment was performed under same conditions with indoor RH regulated to 40%.The ESC turned off the outdoor damper to allow minimal outdoor air. The power consumption was reduced from 620 W to 600 W with an energy saving of 3.33%. More experiments will be performed in warmer weather in February and March to further validate the performance of the ESC controller

    Counselor Education Admissions: A Selection Process that Highlights Candidate Self-Awareness and Personal Characteristics

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    This article describes an experiential model for applicant selection in a master‟s level counselor education graduate program. While nonintellectual aspects are emphasized in the model, some traditional measures are also considered. The program‟s emphasis on counselor self-awareness and personal characteristics is articulated. A discussion of the model\u27s rationale, the interpersonal aspects of candidate selection and a discussion of the group- oriented interviewing process is provided. Contemporary and future challenges for application selection models in Counselor Education programs are articulated

    Self-optimizing Control of Cooling Tower for Efficient Operation of Chilled Water Systems

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    The chilled-water systems, mainly consisting of electric chillers and cooling towers, are crucial for the ventilating and air conditioning systems in commercial buildings. Energy efficient operation of such systems is thus important for the energy saving of commercial buildings. This paper presents an extremum seeking control (ESC) scheme for energy efficient operation of the chilled-water system, and presents a Modelica based dynamic simulation model for demonstrating the effectiveness of the proposed control strategy. The simulated plant consists of a water-cooled screw chiller and a mechanical-draft counter-flow wet cooling tower. The ESC scheme takes the total power consumption of the chiller compressor and the tower fan as feedback, and uses the fan speed setting as the control input. The inner-loop controllers for the chiller operation include two proportional-integral (PI) control loops for regulating the evaporator superheat and the chilled water temperature. Simulation was conducted on the dynamic simulation model of the whole plant including the screw chiller and the cooling tower for different scenarios. The simulation results demonstrated the effectiveness of the proposed ESC strategy in searching for the optimal tower fan speed set-point under tested circumstances, and the potential for energy saving is also evaluated
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