Through natural and constructed elements, landscape architects design public landscapes to engage the public in the great outdoors. While many local governments and designers actively create landscapes to keep the unsheltered and homeless out of public spaces, keep water in storm drains, and keep native plants on the periphery of the public landscape, my project, Safe Haven, is about creating an inclusive public landscape for people, water, and native plants. Preliminary research into the history of property ownership, discrimination, economic inequality, and government programs for the unsheltered created a picture of why certain demographics struggle with housing. Case studies of homeless encampments in the Washington DC area of NOMA, Abbot's Camp in Austin, Texas, and car camping in San Diego, California, and Seattle, Washington, gave insight into the current landscape needs of unsheltered people. Studies of the watershed and plants native to the site inspired a water retention system and a seasonal pallet of plants. The design incorporates existing infrastructure, new buildings, a natural playground, wilderness camping, a Mount Vernon-inspired vegetable garden, and a sunken garden designed to retain water while showcasing native plants. Describing the design are narratives sharing the perspective of water, native plants, the unsheltered, and the homeless. Lady Landscape guides the stories and offers her views on the responsibilities of a landscape architect. / Master of Landscape Architecture / Inclusive landscapes create a vision of places where children, older adults, people with and without disabilities enjoy the beauty of Mother Nature. There are ADA regulations that ensure everyone can be accommodated within a public landscape, but those regulations don't extend to the needs of unsheltered or homeless people. Their needs to enjoy public parks and recreation areas are different from housed people. They're looking for a home, and many public spaces are built to deter them from living on public lands. My project is a landscape designed with the unsheltered and homeless as the primary client. My project is about creating room for people without homes in the landscape - offering them dignity and meeting them where they are. Researching the needs of the homeless and what is presently available helped guide my design. After choosing an appropriate site in Fairfax City, Virginia, it became apparent that water and native plants would also need a home in this project. A thorough study of the water pattern over the area informed design elements that gave water a home through a Vegetative Swale and Sunken Garden while native plants found space in garden rooms. The thesis is presented as a narrative with Lady Landscape guiding the reader through the design by introducing them to the people and natural elements the landscape offers refuge to.

In order to increase the power density, the discontinuous conducting mode (DCM) and small inductance is adopted for high power bidirectional dc-dc converter. The DCM related current ripple is minimized with multiphase interleaved operation. The turn-off loss caused by the DCM induced high peak current is reduced by snubber capacitor. The energy stored in the capacitor needs to be discharged before device is turned on. A complementary gating signal control scheme is employed to turn on the non-active switch helping discharge the capacitor and diverting the current into the anti-paralleled diode of the active switch. This realizes the zero voltage resonant transition (ZVRT) of main switches. This scheme also eliminates the parasitic ringing in inductor current. This work proposes an inductance and snubber capacitor optimization methodology. The inductor volume index and the inductor valley current are suggested as the optimization method for small volume and the realization of ZVRT. The proposed capacitance optimization method is based on a series of experiments for minimum overall switching loss. According to the suggested design optimization, a high power density hardware prototype is constructed and tested. The experimental results are provided, and the proposed design approach is verified. In this dissertation, a general-purposed power stage model is proposed based on complementary gating signal control scheme and derived with space-state averaging method. The model features a third-order system, from which a second-order model with resistive load on one side can be derived and a first-order model with a voltage source on both sides can be derived. This model sets up a basis for the unified controller design and optimization. The Δ-type model of coupled inductor is introduced and simplified to provide a more clearly physical meaning for design and dynamic analysis. These models have been validated by the Simplis ac analysis simulation. For power flow control, a unified controller concept is proposed based on the derived general-purposed power stage model. The proposed unified controller enables smooth bidirectional current flow. Controller is implemented with digital signal processing (DSP) for experimental verification. The inductor current is selected as feedback signal in resistive load, and the output current is selected as feedback signal in battery load. Load step and power flow step control tests are conducted for resistive load and battery load separately. The results indicate that the selected sensing signal can produce an accurate and fast enough feedback signal. Experimental results show that the transition between charging and discharging is very smooth, and there is no overshoot or undershoot transient. It presents a seamless transition for bidirectional current flow. The smooth transition should be attributed to the use of the complementary gating signal control scheme and the proposed unified controller. System simulations are made, and the results are provided. The test results have a good agreement with system simulation results, and the unified controller performs as expected. / Ph. D.