Energy-efficient optical crossbars on chip with multi-layer deposited silicon

A novel and widespread business model in cloud computing is to provide on-demand software as a service (SaaS) over the Internet. The software runs on a server and the user access it through an Internet connection. A single application instance can be shared by multiple users which provide a cost-effective solution to SaaS providers. Varying requirements from multiple users increase complexity in SaaS application design. The success of SaaS depends on its design. SaaS is different than traditional web-based application, so traditional application design model cannot full fill many SaaS specific design requirements. This paper provides a better understanding of key design factors in SaaS development process which results in a successful SaaS product following an improved design process. This study identifies key design factors through literature review and provides guidelines for key design factors on the SaaS application development. Ultimately, it will be beneficial for SaaS developers to improve the SaaS application development process and have a positive impact on the final product.

Designing emotionally evocative homepages: an empirical study of the quantitative relations between design factors and emotional dimensions

Injecting CO2 in subsurface formations bearing brine creates different storage mechanisms. Firstly, CO2 will have an upward movement due to the buoyancy and it will be trapped below a geological barrier. During this stage of flow brine starts to imbibe into the pore spaces already occupied by CO2. Because of the wetting behavior of the system and CO2-brine capillary pressure, fractions of CO2 remain as residual saturation in the pore spaces. This is an important phenomenon that affects the storage capability and security. Later, and in a long term process, CO2 starts to dissolute into the brine and its density will be increased; and as a result convection mixing phenomena will starts.To clarify the trapping mechanism, two different issues are discussed. One is the one dimensional, two phase behavior during CO2 injection and the second is the water imbibition process that includes the trapping mechanism. By arranging the flow equations and normalizing them by dimensionless parameters, main scaling parameters that define the physics in each problem are obtained. These parameters are CO2-brine mobility ratio and special gravity and capillary dimensionless numbers for each problem. In the water imbibition problem, hysteresis in relative permeability results in modifications to the dimensionless scaling parameters. These parameters are key factors in design and scaling of the experimental measurements to the simulation and analytical results.To verify the analytical analysis, a numerical simulation model is constructed for the problems. Reservoir parameters of the Sleipner CO2 storage reservoir and the Viking formation (Bennion et. al. 2008) are used in this study in order to construct the model. This time, dimensionless parameters are defined according to the reservoir parameters. Analytical models are established based on simplifying assumptions, while simulation results are dependent on key scaling parameters obtained from analytical clarification. This means that they are good representatives of phenomena at reservoir conditions and can be used as a conceptual model before performing a fine scale, time consuming reservoir simulation study.

Insufficient wellbore cleaning prior the cementing job is considered to be the biggest single factor leading to poor zonal isolation results. A mud-spacer-cement program with suitable fluid needs to be carefully engineered for the given wellbore conditions to improve cementing quality. We discuss optimum spacer design features which are critical for the successful cementation of deep deviated HPHT wells containing heavy oil based muds and review a simulated scenario. Advanced lab test methodologies beyond industry standards are utilized to model more accurately the given complex downhole conditions. A simulated >20,000 ft highly deviated wellbore was characterized by HPHT bottomhole conditions and the rheological performance of the cement spacer was critical to job success. The well needed a stable cement spacer that would not settle-out on the low side of the >14,000 ft horizontal section, which would potentially put the well at risk. The 16.17 ppg mud required an even higher-density spacer system to clean it effectively. But conventional high-density spacer systems only compound the settling challenge and the well's anticipated bottomhole temperature of 350°F was expected to compromise any additives that might stabilize the fluid systems. Therefore a lab study about spacer stability was performed using a HPHT rheometer and the dynamic settling test – an industry standard which was actually established for cement slurries but not for spacer fluids. We found that a conventional spacer failed at 350°F by showing a rapid decline in rheology to almost zero viscosity and severe settling. To overcome the settling issue, provide stability, and maintain a sufficiently high rheology profile at given 350°F, we re-designed the spacer by using a modified biopolymer which shows a delayed hydration and viscosification over time successfully counteracting the destructive thermal effects. The mud-spacer-cement fluid train was eventually optimized showing good fluid compatibility and maintaining within the narrow, 1.6 ppg margin that separated the pore pressure from the fracture gradient. The cementing job was designed using an advanced fluid displacement software, which predicted high mud removal efficiency under these challenging conditions. In order to enable proper mud displacement, the Friction Hierarchy—a key design factor that is often difficult to achieve under the extreme HPHT well conditions—was achieved with the new spacer concept.

To accomplish high-bandwidth and low-latency communications among tens or even hundreds of nodes with low power consumption, dual radial and angular grating optical network (DRAGON), a new integrated high-radix strictly nonblocking optical switching fabric, is proposed in this paper. The topology and routing algorithms of DRAGON are discussed, and a formal proof for the strictly nonblocking property is presented. With the loss model developed, we show DRAGON has significantly lower worst-case loss as well as average loss compared with other widely studied integrated nonblocking switching fabrics. In addition, our crosstalk analysis also suggests a lower crosstalk of DRAGON. For example, for 32 wavelength division multiplexing channels, both the worst-case loss and average loss of ${\text{180}}\times {\text{180}}$ DRAGON are around 20 dB lower than crossbar of the same size, and 28 dB lower than ${\text{128}}\times {\text{128}}$ Benes. Furthermore, due to the strictly nonblocking property, DRAGON has advantages of smaller communication latency and larger throughput compared with Benes switching fabric.

This paper studies the design of large-scale wireless sensor networks interconnecting several hundred sensor nodes. Given the low computation and battery power capacities of sensor nodes, the key design factors are scalability, energy efficiency and protocol simplicity. In this paper, we present a multi-level, multi-hop sensor network architecture for a network consisting of a few hundred nodes that communicate sensor data to a base-station. We present a unified framework that encompasses network organization, medium access control (MAC) and routing protocols. The MAC protocol, based on TDMA access, is designed to be collision-free, energy-efficient and fair. The routing protocol is multi-hop and uses a simple layered (tree-based) scheme. This reduces the number of control packets that need to be transmitted and hence reduces energy and computation costs. The performance of the network, in terms of delay, throughput, energy consumption and network lifetimes, is also studied in detail using discrete-event simulation.

The frequency shift and amplitude change in Schumann resonance (SR) as a precursor of some moderate to strong earthquakes was observed and reported. Co-seismic SR variation could be occurring at even large magnitude and scale. In this study, we first model Schumann resonance associated with the occurrence of an earthquake and assess the SR variation recorded from an earth-based sensor network. Based on the computer simulation results, we then propose a wireless observation system to monitor SR as a potential precursor prior to an earthquake using a wireless sensor network (WSN). A WSN based on single antenna wireless sensor nodes are cooperated to establish a multiple-antenna WSN that is called virtual MIMO-WSN. Virtual MIMO-WSN is adjustable and tunable to monitor electromagnetic signals in different frequencies based on the number of the cooperative wireless sensor nodes. An electromagnetic map could then be generated by activating a virtual MIMO-WSN in specific direction by switching on/off certain sensor nodes based on their location (also known as beamforming). Cost effectiveness, system scalability, ease of deployment, adjustability in frequency tuning, and reliability in ELF/VLF direction-finding are the key design factors in virtual MIMO-WSN to overcome the bottlenecks in the existing techniques for ELF/VLF monitoring systems. Simulation results are used to evaluate these quality indices of the proposed virtual MIMO-WSN.

Due to reduced manufacturing, transportation, and installation costs, the two-blade wind turbines (Two-BWT) are a viable option for offshore wind farms. So far, there is no mature design model for offshore Two-BWT. This paper proposes an aerodynamic design method for offshore Two-BWT blades using the blade element momentum (BEM) theory. This method calculates the power coefficient of the Two-BWT by analogy with the three-blade wind turbines (Three-BWT), and then determines the wind rotor diameter. Then, the airfoil, chord length, and twist angle are taken as the key design factors. Furthermore, the piecewise combination method (PCM) for airfoil distribution, the three-point sine method (Three-PSM) for chord length distribution, and the two-point sine method (Two-PSM) for torsion angle distribution are adopted, respectively. Subsequently, the minimum rotational speed, under the rated wind speed and rated power, is taken as the optimization objective to establish the optimization model. The global flow field of Two-BWT is constructed based on CFD technology, and the characteristics of wind speed distribution and blade pressure distribution in the flow field are investigated. Finally, the CFD results are compared with the results of the BEM theory, and the consistency of the results also shows the feasibility of the design method.

Board level temperature cycle and drop test reliability data was collected for 23 × 23 mm FCBGA packages. Two different bare die thicknesses, the effect of lidded configuration, and two different board thicknesses were evaluated as key design factors. Different package warpage shapes modulated by two different assembly process flows, two different ball attach reflow profiles and ball attach rework were evaluated as key package process parameters. Two temperature cycle conditions were applied including JESD22-A104D Condition G and Condition N. Drop-shock test was also performed under JESD22-B104C Condition A and Condition B. The data suggested that bare die thickness and lidded configuration had significant impact on both temperature cycle and drop test reliability while the process parameters studied did not have a statistically significant effect. Composite substrate and board mechanical properties were characterized. Finite element analysis was conducted to interpret temperature cycle solder ball failure location considering both peeling stress and inelastic strain energy density.

With the worldwide dissemination of the “green development” concept and the advancement of China’s new rural construction, the sustainable development of rural residences has gained significant attention within the construction industry. This article focuses on large-scale prefabricated insulation block houses used in China’s cold regions, specifically examining the case of Defa Village in Nenjiang City, Heilongjiang Province. By utilizing thermal imaging cameras, the thermal bridge parts of these houses are detected, and a finite element model is established to optimize the comprehensive heat transfer coefficient of these areas. This optimization is achieved by expanding the insulation layer and implementing low thermal bridge structures, ultimately enhancing the insulation and energy-saving efficiency of the houses. Simultaneously, an energy-saving analysis is conducted based on an optimized enclosure structure scheme, considering seven key design factors that influence building energy consumption: span, depth, clear height, and window-to-wall ratio in all four directions. Through a comprehensive experimental method, the building energy consumption is evaluated, and a scheme with optimal values is proposed. The results demonstrate that the insulation block walls and the main structures with expanded insulation layers and low thermal bridge structures are easier to construct. When compared to the original scheme, the comprehensive heat transfer coefficient of the walls is reduced by 54.82%, while that of the beams and columns is reduced by 97%. Implementing the optimal value scheme leads to a reduction of 66.83% in the building’s overall energy consumption. This research provides valuable guidance for the design and construction of large-scale insulated block rural residences, revealing the substantial potential of rural residences in terms of energy-saving and emission reduction.

This paper presents methodologies for modeling and designing the target architecture for the Global Command and Control System (GCCS). The target GCCS architecture advances information processing and communications technologies to support a wide variety of command and control missions and functions. The GCCS requires reliable high-speed networking, multimedia conferencing, distributed simulation, and training. In addition, GCCS accommodates many information applications through shared processing, distributed data, multimedia communications, and centralized monitoring and control. All existing applications will be modernized and consolidated into a common operating environment. System characterization, interoperability of functional applications, target architecture design, capacity sizing, and optimum allocations of information technology resources are key design factors. The performance analysis, management and control, and operational effectiveness of involved systems are also discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

With respect to the light environment of the exhibition halls for Chinese calligraphy and painting works in the museums, the daylighting design in these display spaces have been studied, the key design factors, such as daylighting pattern, and arrangement of exhibits are examined and explored by field trips. Then, the display spaces are divided into diverse categories whose sky light environments are predicted by the demands of exhibits. Under changed daylighting situations, the daylight parameters, i.e., daylight factor (DF) and DF uniformity, discomfort glare index (DGI) and luminance distribution are calculated. Thus, the proper daylighting pattern and elements in the exhibition halls will be decided. The optimization strategies that optimize the parameters of daylighting patterns and elements are presented. The studies have shown that the daylighting quality will improved by the implement of optimal design, and good luminance environment in the calligraphy and painting exhibition halls are obtained.

Comprehensive magnetic properties of the laminated silicon steels are key factors in magnetic core design, which should be measured and modeled by using new testing method. Comparing with the traditional Epstein Frame and Single Sheet Tester (SST), a novel Three-dimensional (3-D) magnetic properties tester has been designed for complex magnetic properties measurement of the laminated silicon steels. Grain oriented (GO) and non-grain oriented silicon steel samples are magnetized under alternating and rotational excitation considering the laminated direction. Both magnetic hysteresis and core loss features of the laminated silicon steels are measured and analyzed. This study can provide dynamic and comprehensive data to design and evaluate performance of the electrical machines and power transformers.

This paper presents the initial determination of key factors of design desirability for 3D printed occupational therapy products in rural communities in Sub-Saharan Africa. As most disabled persons worldwide are living in low-income countries, it is crucial to have supply chains to provide access to appropriate therapy tools. 3D printing technology can address poverty in these countries by addressing individual product needs and improving industrial capabilities. It has been proven that 3D printing technology can be employed to produce feasible and viable products, but the key issue of product desirability is currently unaddressed. This paper addresses the problem of misunderstood design desirability to provide appropriate occupational therapy tools in this market. To address this issue, all known occupational therapists in Kisumu County, Kenya were interviewed about eleven key factors of design desirability. Of the ten hospitals with occupational therapy programs, six occupational therapists were interviewed, first informally to understand their experience and perception of 3D printing and then formally to understand their unique desires for appropriate products. These interviews suggested that portability, customizability, and cost are the most important considerations when designing new occupational therapy products. Patients cannot afford transportation to large hospitals, increasing the value of home programs. Patient needs are not met by traditional devices, and therapists are eager to work with designers to create appropriate, customized products. Occupational therapy is viewed as less critical than other departments, so budgets are low. To make claims with greater specificity, therapists in the additional 47 counties in Kenya need to be interviewed. The length and depth of the survey should be extended to provide better, quantitative data. Once a specific determination is made, these desirability factors should be used to guide product design of 3D printed occupational therapy tools to provide appropriate occupational therapy tools, increasing the availability of effective care for patients seeking education and employment.

Macromolecule-based therapeutic agents, particularly proteins, antigens, monoclonal antibodies, transcription factors, nucleic acids, and gene editing enzymes, have the potential to offer cures for previously untreatable diseases. However, they present an enormous delivery challenge due to poor absorption and rapid metabolism in the body. Polymersomes have tremendous potential in delivering these agents to their desired intracellular location due to increased circulation times, decreased macromolecule degradation, and decreased immune responses. In this Review, we highlight the key factors in design, development, and improved performance of these vesicles for macromolecular delivery. The recent progress made toward preclinical application of these vesicles for protein and gene delivery is also covered.