Methodology for tidal turbine representation in ocean circulation model

The present method proposes the use and adaptation of ocean circulation models as an assessment tool framework for tidal current turbine (TCT) array layout optimization. By adapting both momentum and turbulence transport equations of an existing model, the present TCT representation method is proposed to extend the actuator disc concept to 3-D large-scale ocean circulation models. Through the reproduction of experimental flume tests and grid dependency tests, this method has shown its numerical coherence as well as its ability to simulate accurately both momentum and turbulent turbine-induced perturbations in both near and far wakes in a relatively short period of computation time. Consequently the present TCT representation method is a very promising basis for the development of a TCT array layout optimization tool

ポータビリティを意識したCMOSミックスドシグナルVLSI回路設計手法に関する研究

本研究は、半導体上に集積されたアナログ・ディジタル・メモリ回路から構成されるミクストシグナルシステムを別の製造プロセスへ移行することをポーティングとして定義し、効率的なポーティングを行うための設計方式と自動回路合成アルゴリズムを提案し、いくつかの典型的な回路に対する設計事例を示し、提案手法の妥当性を立証している。北九州市立大

Healthcare providers' perception of design factors related to physical environments in hospitals

Research indicates that staff wellbeing, productivity and satisfaction are linked with a hospital’s physical environment, in particular the aspects that are determined during early design stages of a building’s lifecycle. Incorporating healthcare providers’ perspectives during the design of a facility is, therefore, essential to create an effective therapeutic environment. Past research on physical environments in hospitals focused mostly on user satisfaction and was linked with service delivery in a specific setting. Research findings seldom provided useful insights into user perspectives on design related aspects that had the potential to affect their interaction with the environment. This research was aimed at filling this gap by exploring healthcare providers’ perception of physical environment design factors in hospitals. A 16-item questionnaire was used to gather perspectives of nurses, doctors and administrative staff in two Chinese hospitals, with a response rate of 77.3% (N = 304). Descriptive, principal component analysis and statistical tests were applied on the responses to investigate the relationship between perceptions of design factors and demographic and work related variables. Three principal components were identified, namely spatial, maintenance and environmental design. The identified components had good correspondence with previous research on behavioral and environmental psychology. Female healthcare providers were found to be more perceptive about factors related to sensory environments such as visual, acoustic and olfactory, compared to their male counterparts. The working pattern and length of service had associations with perceptions of maintenance and environmental design factors. Respondents ranked abstract and more subjective design factors such as aesthetics and the presence of coordinated art objects lower than the factors generally associated with the safe and efficient delivery of service

Analog layout design automation: ILP-based analog routers

The shrinking design window and high parasitic sensitivity in the advanced technology have imposed special challenges on the analog and radio frequency (RF) integrated circuit design. In this thesis, we propose a new methodology to address such a deficiency based on integer linear programming (ILP) but without compromising the capability of handling any special constraints for the analog routing problems. Distinct from the conventional methods, our algorithm utilizes adaptive resolutions for various routing regions. For a more congested region, a routing grid with higher resolution is employed, whereas a lower-resolution grid is adopted to a less crowded routing region. Moreover, we strengthen its speciality in handling interconnect width control so as to route the electrical nets based on analog constraints while considering proper interconnect width to address the acute interconnect parasitics, mismatch minimization, and electromigration effects simultaneously. In addition, to tackle the performance degradation due to layout dependent effects (LDEs) and take advantage of optical proximity correction (OPC) for resolution enhancement of subwavelength lithography, in this thesis we have also proposed an innovative LDE-aware analog layout migration scheme, which is equipped with our special routing methodology. The LDE constraints are first identified with aid of a special sensitivity analysis and then satisfied during the layout migration process. Afterwards the electrical nets are routed by an extended OPC-inclusive ILP-based analog router to improve the final layout image fidelity while the routability and analog constraints are respected in the meantime. The experimental results demonstrate the effectiveness and efficiency of our proposed methods in terms of both circuit performance and image quality compared to the previous works

A simple layout optimization formulation for load-carrying tensegrity structures

Traditional tensegrity structures comprise isolated compression members lying inside a continuous network of tension members. In this contribution, a simple numerical layout optimization formulation is presented and used to identify the topologies of minimum volume tensegrity structures designed to carry external applied loads. Binary variables and associated constraints are used to limit (usually to one) the number of compressive elements connecting a node. A computationally efficient two-stage procedure employing mixed integer linear programming (MILP) is used to identify structures capable of carrying both externally applied loads and the self-stresses present when these loads are removed. Although tensegrity structures are often regarded as inherently ‘optimal’, the presence of additional constraints in the optimization formulation means that they can never be more optimal than traditional, non-tensegrity, structures. The proposed procedure is programmed in a MATLAB script (available for download) and a range of examples are used to demonstrate the efficacy of the approach presented

A novel deep submicron bulk planar sizing strategy for low energy subthreshold standard cell libraries

Engineering andPhysical Science ResearchCouncil (EPSRC) and Arm Ltd for providing funding in the form of grants and studentshipsThis work investigates bulk planar deep submicron semiconductor physics in an attempt to improve standard cell libraries aimed at operation in the subthreshold regime and in Ultra Wide Dynamic Voltage Scaling schemes. The current state of research in the field is examined, with particular emphasis on how subthreshold physical effects degrade robustness, variability and performance. How prevalent these physical effects are in a commercial 65nm library is then investigated by extensive modeling of a BSIM4.5 compact model. Three distinct sizing strategies emerge, cells of each strategy are laid out and post-layout parasitically extracted models simulated to determine the advantages/disadvantages of each. Full custom ring oscillators are designed and manufactured. Measured results reveal a close correlation with the simulated results, with frequency improvements of up to 2.75X/2.43X obs erved for RVT/LVT devices respectively. The experiment provides the first silicon evidence of the improvement capability of the Inverse Narrow Width Effect over a wide supply voltage range, as well as a mechanism of additional temperature stability in the subthreshold regime. A novel sizing strategy is proposed and pursued to determine whether it is able to produce a superior complex circuit design using a commercial digital synthesis flow. Two 128 bit AES cores are synthesized from the novel sizing strategy and compared against a third AES core synthesized from a state-of-the-art subthreshold standard cell library used by ARM. Results show improvements in energy-per-cycle of up to 27.3% and frequency improvements of up to 10.25X. The novel subthreshold sizing strategy proves superior over a temperature range of 0 °C to 85 °C with a nominal (20 °C) improvement in energy-per-cycle of 24% and frequency improvement of 8.65X. A comparison to prior art is then performed. Valid cases are presented where the proposed sizing strategy would be a candidate to produce superior subthreshold circuits

A vector light sensor for 3D proximity applications: Designs, materials, and applications

In this thesis, a three-dimensional design of a vector light sensor for angular proximity detection applications is realized. 3D printed mesa pyramid designs, along with commercial photodiodes, were used as a prototype for the experimental verification of single-pixel and two-pixel systems. The operation principles, microfabrication details, and experimental verification of micro-sized mesa and CMOS-compatible inverse vector light pixels in silicon are presented, where p-n junctions are created on pyramid’s facets as photodiodes. The one-pixel system allows for angular estimations, providing spatial proximity of incident light in 2D and 3D. A two-pixel system was further demonstrated to have a wider-angle detection. Multilayered carbon nanotubes, graphene, and vanadium oxide thin films as well as carbon nanoparticles-based composites were studied along with cost effective deposition processes to incorporate these films onto 3D mesa structures. Combining such design and materials optimizations produces sensors with a unique design, simple fabrication process, and readout integrated circuits’ compatibility. Finally, an approach to utilize such sensors in smart energy system applications as solar trackers, for automated power generation optimizations, is explored. However, integration optimizations in complementary-Si PV solar modules were first required. In this multi-step approach, custom composite materials are utilized to significantly enhance the reliability in bifacial silicon PV solar modules. Thermal measurements and process optimizations in the development of imec’s novel interconnection technology in solar applications are discussed. The interconnection technology is used to improve solar modules’ performance and enhance the connectivity between modules’ cells and components. This essential precursor allows for the effective powering and consistent operations of standalone module-associated components, such as the solar tracker and Internet of Things sensing devices, typically used in remote monitoring of modules’ performance or smart energy systems. Such integrations and optimizations in the interconnection technology improve solar modules’ performance and reliability, while further reducing materials and production costs. Such advantages further promote solar (Si) PV as a continuously evolving renewable energy source that is compatible with new waves of smart city technology and systems

Optimal treatment allocations in space and time for on-line control of an emerging infectious disease

A key component in controlling the spread of an epidemic is deciding where, whenand to whom to apply an intervention.We develop a framework for using data to informthese decisionsin realtime.We formalize a treatment allocation strategy as a sequence of functions, oneper treatment period, that map up-to-date information on the spread of an infectious diseaseto a subset of locations where treatment should be allocated. An optimal allocation strategyoptimizes some cumulative outcome, e.g. the number of uninfected locations, the geographicfootprint of the disease or the cost of the epidemic. Estimation of an optimal allocation strategyfor an emerging infectious disease is challenging because spatial proximity induces interferencebetween locations, the number of possible allocations is exponential in the number oflocations, and because disease dynamics and intervention effectiveness are unknown at outbreak.We derive a Bayesian on-line estimator of the optimal allocation strategy that combinessimulation–optimization with Thompson sampling.The estimator proposed performs favourablyin simulation experiments. This work is motivated by and illustrated using data on the spread ofwhite nose syndrome, which is a highly fatal infectious disease devastating bat populations inNorth America

Analysis of Thermal Interconnectivity of Utilities in Rural Alaska

Presented to the Faculty of the University of Alaska Anchorage in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCEThroughout the arctic there are two primary community utilities with dramatically contrary thermodynamic concerns. These are the intensely exothermic diesel electric power generation, and the strongly endothermic water and sewer utility. In this context exothermic processes must expel excess heat while endothermic process requires heat input. Failure of engineers, community planners, funding agencies, and interest groups to recognize the full social, economic, and environmental impact to the sustainability of utilities has come at tremendous cost. This is exemplified in many remote Alaskan communities such as Toksook Bay, Minto, Deering, and Kotlik