Profile of planning: A study of a three-year project on the implementation of collaborative library media programs

The implementation of collaborative planning and teaching models in ten flexibly scheduled elementary and middle school library media centers was studied to determine which factors facilitated the collaborative planning process and to learn what occurs when library media specialists (LMSs) and classroom teachers (CTs) plan together. In this qualitative study, 61 principals, CTs, and LMSs were interviewed on a range of topics including the principal's role, school climate, the value of team planning, the importance of information literacy instruction, and the ideal learning environment. Other data sources were observations, videotapes of planning sessions, and documents. This three-year school reform effort was funded by the Library Power Project to improve library programs, to encourage collaborative planning, and to increase curricular integration of information literacy skills instruction. ^ The findings included a description of typical planning sessions and the identification of several major factors which impacted the success of collaborative planning: the individuals involved, school climate, time for planning, the organization of the school, the facility and collection, and training. Of these factors, the characteristics and actions of the people involved were most critical to the implementation of the innovation. The LMS was the pivotal player and, in the views of CTs, principals, and LMSs themselves, must be knowledgeable about curriculum, the library collection, and instructional design and delivery; must be open and welcoming to CTs and use good interpersonal skills; and must be committed to information literacy instruction and willing to act as a change agent. The support of the principal was vital; in schools with successful programs, the principal served as an advocate for collaborative planning and information literacy instruction, provided financial support for the library program including clerical staff, and arranged for LMSs and CTs to have time during the school day to plan together. ^ CTs involved in positive planning partnerships with LMSs were flexible, were open to change, used a variety of instructional materials, expected students to be actively involved in their own learning, and were willing to team teach with LMSs. Most CTs planning with LMSs made lesson plans in advance and preferred to plan with others. Also, most CTs in this study planned with grade level or departmental groups, which expedited the delivery of information literacy instruction and the effective use of planning time. ^ Implications of the findings of this research project were discussed for individual schools, for school districts, and for colleges and universities training LMSs, CTs, and administrators. Suggestions for additional research were also included. ^

Switching patterns and steady-state analysis of grid-connected and stand-alone single-stage boost-inverters for PV applications

Renewable or sustainable energy (SE) sources have attracted the attention of many countries because the power generated is environmentally friendly, and the sources are not subject to the instability of price and availability. This dissertation presents new trends in the DC-AC converters (inverters) used in renewable energy sources, particularly for photovoltaic (PV) energy systems. A review of the existing technologies is performed for both single-phase and three-phase systems, and the pros and cons of the best candidates are investigated. In many modern energy conversion systems, a DC voltage, which is provided from a SE source or energy storage device, must be boosted and converted to an AC voltage with a fixed amplitude and frequency. A novel switching pattern based on the concept of the conventional space-vector pulse-width-modulated (SVPWM) technique is developed for single-stage, boost-inverters using the topology of current source inverters (CSI). The six main switching states, and two zeros, with three switches conducting at any given instant in conventional SVPWM techniques are modified herein into three charging states and six discharging states with only two switches conducting at any given instant. The charging states are necessary in order to boost the DC input voltage. It is demonstrated that the CSI topology in conjunction with the developed switching pattern is capable of providing the required residential AC voltage from a low DC voltage of one PV panel at its rated power for both linear and nonlinear loads. In a micro-grid, the active and reactive power control and consequently voltage regulation is one of the main requirements. Therefore, the capability of the single-stage boost-inverter in controlling the active power and providing the reactive power is investigated. It is demonstrated that the injected active and reactive power can be independently controlled through two modulation indices introduced in the proposed switching algorithm. The system is capable of injecting a desirable level of reactive power, while the maximum power point tracking (MPPT) dictates the desirable active power. The developed switching pattern is experimentally verified through a laboratory scaled three-phase 200W boost-inverter for both grid-connected and stand-alone cases and the results are presented.

Switching Patterns and Steady-State Analysis of Grid-Connected and Stand-Alone Single-Stage Boost-Inverters for PV Applications

Renewable or sustainable energy (SE) sources have attracted the attention of many countries because the power generated is environmentally friendly, and the sources are not subject to the instability of price and availability. This dissertation presents new trends in the DC-AC converters (inverters) used in renewable energy sources, particularly for photovoltaic (PV) energy systems. A review of the existing technologies is performed for both single-phase and three-phase systems, and the pros and cons of the best candidates are investigated. In many modern energy conversion systems, a DC voltage, which is provided from a SE source or energy storage device, must be boosted and converted to an AC voltage with a fixed amplitude and frequency. A novel switching pattern based on the concept of the conventional space-vector pulse-width-modulated (SVPWM) technique is developed for single-stage, boost-inverters using the topology of current source inverters (CSI). The six main switching states, and two zeros, with three switches conducting at any given instant in conventional SVPWM techniques are modified herein into three charging states and six discharging states with only two switches conducting at any given instant. The charging states are necessary in order to boost the DC input voltage. It is demonstrated that the CSI topology in conjunction with the developed switching pattern is capable of providing the required residential AC voltage from a low DC voltage of one PV panel at its rated power for both linear and nonlinear loads. In a micro-grid, the active and reactive power control and consequently voltage regulation is one of the main requirements. Therefore, the capability of the single-stage boost-inverter in controlling the active power and providing the reactive power is investigated. It is demonstrated that the injected active and reactive power can be independently controlled through two modulation indices introduced in the proposed switching algorithm. The system is capable of injecting a desirable level of reactive power, while the maximum power point tracking (MPPT) dictates the desirable active power. The developed switching pattern is experimentally verified through a laboratory scaled three-phase 200W boost-inverter for both grid-connected and stand-alone cases and the results are presented.