Window Device Research Articles

Downscaling indicators of forest habitat structure from national assessments

Abstract Downscaling is an important problem because consistent large-area assessments of forest habitat structure, while feasible, are only feasible when using relatively coarse data and indicators. Techniques are needed to enable more detailed and local interpretations of the national statistics. Using the results of national assessments from land-cover maps, this paper demonstrates downscaling in the spatial domain, and in the domain of the habitat model. A moving window device was used to measure structure (habitat amount and connectivity), and those indicators were then analyzed and combined with other information in various ways to illustrate downscaling.

Lighting electric power reduction by the window device of prism system for daylighting

Lighting electric power reduction by the window device of prism system for daylighting

Beckett's Windows and the Windowless Self

Beckett uses device that appears open to the outer world, yet is really closed, viewless and practically windowless. From a small frosted skylight of Murphy until the last window of Stirrings Still, the window has kept evoking condition of is sueless room/mind inhabited by protagonists like Murphy, Watt, Malone, and Hamm. Focusing upon the window in Beckett's oeuvre, this article formulates his strategic use of the window device as solipsistic expression, that is, the Leibnizian monadic windowless self.

KISS

The design of concurrent programs is error-prone due to the interaction between concurrently executing threads. Traditional automated techniques for finding errors in concurrent programs, such as model checking, explore all possible thread interleavings. Since the number of thread interleavings increases exponentially with the number of threads, such analyses have high computational complexity. In this paper, we present a novel analysis technique for concurrent programs that avoids this exponential complexity. Our analysis transforms a concurrent program into a sequential program that simulates the execution of a large subset of the behaviors of the concurrent program. The sequential program is then analyzed by a tool that only needs to understand the semantics of sequential execution. Our technique never reports false errors but may miss errors. We have implemented the technique in KISS, an automated checker for multithreaded C programs, and obtained promising initial results by using KISS to detect race conditions in Windows device drivers.

A comparison of the Linux and Windows device driver architectures

In this paper the device driver architectures currently used by two of the most popular operating systems, Linux and Microsoft's Windows, are examined. Driver components required when implementing device drivers for each operating system are presented and compared. The process of implementing a driver, for each operating system, that performs I/O to a kernel buffer is also presented. The paper concludes by examining the device driver development environments and facilities provided to developers by each operating system.

Low-cost networking for dynamic window systems

A low-cost building communications network is needed that would allow individual window and lighting loads to be controlled from an existing enterprise LAN network. This building communications network concept, which we term Integrated Building Environmental Communications System (IBECS™), would enable both occupant-based and building-wide control of individual window, lighting, and sensor devices. IBECS can reduce the cost of systemic control because it allows a drastic cost reduction in per point networking costs. This kind of effort is needed to encourage the control industry to make the commitment to build this technology and to demonstrate to prospective customers that this breakthrough approach to more comprehensive systemic control will provide them with high-quality, convenient control while saving them money. The development and demonstration of network interfaces to DC- and AC-motorized shades and to an electrochromic window are described. The network interfaces enable one to control and monitor the condition of these fenestration appliances from a variety of sources, including a user’s personal computer. By creating a functional specification for an IBECS network interface and testing a prototype, the ability to construct such an interface was demonstrated and the cost-effective price per point better understood. The network interfaces were demonstrated to be reliable in a full-scale test of three DC-motorized Venetian blinds in an open-plan office over 2 years and in limited bench-scale tests of an electrochromic window.

Cyclic environmental testing of electrochromic window devices

We report on a systematic study of the factors affecting the degradation of prototype electrochromic (EC) windows. Our research activities include accelerated lifetime testing, activation analysis studies (AAS), and interfacial analysis studies. EC windows made by several different US companies were subjected to alternate coloring and bleaching voltage cycles while exposed to simulated 1.2-sun UV irradiance in a temperature-controlled environmental chamber. The samples inside the chamber were tested under a matrix of four different environmental test conditions at nominal sample temperatures of 85°C: cycling under irradiance, cycling with no irradiance, irradiance with no cycling, and simple thermal exposure with no cycling. In another accelerated environmental test, we evaluated device performance as a function of activation spectra. We used a series of cut-on filters for performing AAS of photolytically induced degradation of EC window devices. Finally, to identify the interface at which degradation occurs during cycling, we employed electrochemical impedance spectroscopy (ECIS). The ECIS and electro-optical measurements were systematically and periodically repeated to discover any changes in electrochemical behavior as a function of cycling.

00/00911 First a-SiC: H photovoltaic-powered monolithic tandem electrochromic smart window device

Electrochromic (EC) glazings for architectural window systems must have desirable solar control properties, be designed for high-volume manufacture, and exhibit outstanding durability. This paper discusses performance and both real time and accelerated testing of prototype monolithic lithium-ion EC glazings in insulating glass units (IGUs). Outdoor exposure at New Jersey and Arizona (desert) test sites shows good switching performance under the different solar irradiance conditions. Accelerated test results include room temperature and elevated temperature electrochemical cycling, electrochemical cycling in combination with photo/thermal cycling, and temperature/humidity testing of IGUs.

Reoperations After Cochlear Implantation

During the 14-year history of cochlear implantation at Semmelweis University, 95 implantations were performed. There were 15 reoperations, and 2 patients had been operated 3 times. All of the reoperated patients received round window or intracochlear MedEl devices. Successful reinsertion of the electrode was performed without significant difficulty, though in some cases osteoneogenesis was found in the round window or in the scala tympani. None of the patients suffered any inner ear abnormalities due to the first implant, and even the patient with a third implant in the same ear had excellent results and obtained better discrimination scores with the new device. In the authors' opinion, on the basis of the accumulated experience of nearly 100 implantations and 15 reoperations, replacement of the early generation extracochlear implants is most advisable and can be accomplished without adverse effects.

Modeling and optimization of InGaAs infrared photovoltaic detectors

The performance of In x Ga 1− x As detectors operating in the 2–3.4 μm spectral range and temperature of 300 K has been analyzed theoretically as a function of wavelength, band gap and doping level with special emphasis on 2–2.5 μm and 3–3.5 μm atmospheric window devices. The calculations show that the dominant generation–recombination mechanism in p-type, intrinsic and in a lightly doped n-type InGaAs is the spin split-off band Auger process (AS). Since the AS generation increases with the square of the hole concentration, the minimum thermal generation and the best performance can be obtained using moderately doped n-type material as the absorber region of a photovoltaic device. In principle, the ultimate performance can be achieved in the optimized homojunction devices with relatively thick n-type absorber region forming n–p junction with a thin p-type material. N-type doping of absorber region of InGaAs photodiodes at 300 K changes from 1×10 14 to 5.2×10 15 cm −3 for devices optimized for operation at 2 and 3.4 μm wavelength, respectively.

Improved ultraviolet quantum efficiency using a semitransparent recessed window AlGaN/GaN heterojunction p-i-n photodiode

We report on the improved quantum efficiency of GaN-based ultraviolet heterojunction photodiodes using a semitransparent recessed window device structure. At a reverse bias of −5 V the quantum efficiency was ∼57% at the band edge, and remained relatively flat down to ∼330 nm after which some absorption in the p-AlGaN layer became evident. The quantum efficiency only gradually declines after this point, remaining >20% at 280 nm. We attribute these results to avoidance of the optical dead space at the surface of GaN homojunction p-i-ns. The semitransparent p-AlGaN layer was comparatively resistive, causing an electric field crowding effect which resulted in a spatially nonuniform temporal behavior.

First a-SiC : H photovoltaic-powered monolithic tandem electrochromic smart window device

We report on the first monolithic, amorphous-silicon-based, photovoltaic-powered electrochromic window coating. The coating employs a wide band gap a-Si 1− x C x : H n–i–p photovoltaic (PV) cell as a semitransparent power supply, and an Li y WO 3/LiAlF 4/V 2O 5 electrochromic (EC) device as an optical-transmittance modulator. The EC device is deposited directly on top of a PV device that coats a glass substrate. The a-Si 1− x C x : H PV cell has a Tauc gap of 2.2 eV and a transmittance of 80% over a large portion of the visible light spectrum. We reduced the thickness of the device to about 600 Å while maintaining a 1-sun open-circuit voltage of 0.9 V and short-circuit current of 2 mA/cm 2. By employing the LiAlF 4 as the Li + ion electrolyte, the parasitic electronic current through the device has been significantly reduced (<10 μA/cm 2 under 1 V bleaching voltage). By properly controlling y and the thickness of each layer, the coloration and bleaching voltage of the EC device could be adjusted within the range of −0.6 to −1.3 V (coloring) and 0.1–0.6 V (bleaching) for compatibility with the underlying PV cell. Our prototype 16 cm 2 PV/EC device modulates the transmittance by more than 60% over a large portion of the visible spectrum. Its color is pale yellow at bleached state and dark blue at colored state. The coloring and bleaching times of the electrochromic device are approximately 2 min under normal operating conditions (±1 V). The device is hermetically sealed for a long lifetime.

Electrochromic behavior in CVD grown tungsten oxide films

Solid state electrochemical devices (ECDs) for smart windows, large area displays and automobile rearview mirrors are of considerable technological and commercial interest. In this paper, we studied the electrochromic properties of amorphous and polycrystalline CVD carbonyl tungsten oxide films and the possibility for sol–gel thin TiO 2 film to play the role of passive electrode in an electrochromic window with solid polymer electrolyte.

Digitally controlled fault-tolerant multiwavelength programmable fiber-optic attenuator using a two-dimensional digital micromirror device

A digitally controlled multiwavelength variable fiber-optic attenuator using a two-dimensional digital micromirror device (DMD) is introduced. The results from an experimental four-wavelength (i.e., 1546.92, 1548.52, 1550.12, and 1551.72 nm) proof-of-concept attenuator indicate a 26-dB dynamic range and 11-bit resolution. The measured attenuator average coherent optical cross talk per wavelength channel is -38 dB , limited by the additive noise resulting from the nonideal isolation of the optical circulator and the attenuator module. The average optical loss for our experimental attenuator is 15 dB and is limited mainly by the visible-mode DMD that is used as a 1550-nm infrared window device. Our theoretical estimate of a <8-dB loss optimized attenuator can be used for equalization in multiwavelength fiber-optic communications with as many as 108 wavelengths.

Debouncing the speech button: A sliding capture window device for synchronizing turn-taking

When human beings converse, they alternate between talking and listening. Participating in such turntaking behaviors is more difficult for machines that use speech recognition to listen and speech output to talk. This paper describes an algorithm for managing such turn-taking through the use of a sliding capture window. The device is specific to discrete speech recognition technologies that do not have access to echo cancellation. As such, it addresses those inexpensive applications that suffer the most from turn-taking errors—providing a “speech button” that stabilizes the interface. Correcting for short-lived turn-taking errors can be thought of as “debouncing” the button. An informal study based on ten subjects using a voice dialing application illuminates the design.

GaInAs/AlGaInAs Semiconductor Lasers with AlAs Oxide Current Confinement Structure

An AlAs oxide current confinement structure based on an InP substrate has been demonstrated for the first time to realize low threshold long wavelength surface emitting lasers. The oxidized width is confirmed to be well controllable by choosing suitable oxidation time and temperature. We fabricated an metalorganic chemical vapor deposition (MOCVD) grown 1.65-µ m wavelength GaInAs/AlGaInAs multiple quantum well (MQW) edge emitting laser with the AlAs-oxide confinement structure of 3 µ m-wide and 15 µ m-wide windows. A 3 µ m-wide window oxidized laser having uncoated facets exhibits a threshold of 51 mA for device with a 800-µ m-long cavity. We have obtained a threshold current density of 1.3 kA/cm2 for 3 µ m-wide window devices. The results show a potential application of the proposed structure for low threshold long-wavelength surface emitting lasers.

Australia

This overview of computer graphics education in Australia offers a few surprises in the diversity demonstrated by university curricula, and the languages and hardware used. Computer graphics is taught as a third year course at most Australian universities, with some universities also offering an additional advanced graphics course at the fourth year level.Most universities include what has evolved into a set of core topics that are common to most graphics courses. Most have also added some extra flavor to their courses by providing some unique topics that, although vaguely related, are not normally considered under the heading of mainstream graphics.Each curriculum generally includes all the expected graphics topics, such as line and curve generation, antialiasing, 2D transformations, 3D transformations and 3D viewing, hidden line and hidden surface algorithms, polygon fill algorithms, clipping, illumination and shading models and solid modeling. A good proportion of universities also include texture mapping, color modeling (e.g., RGB and CIE representations), animation, virtual/synthetic camera modeling, GUI design, splines and Bezier surfaces, fractals, ray tracing and human visual perception. Less commonly offered topics are dithering, radiosity and mathematical models.Approximately half of the courses are centered around device independent graphics standards such as GKS and PHIGS, and the SRGP software package is popular in courses based on the PHIGS standard The core topics in these graphics standards courses include graphical input techniques, graphical display devices for output, coordinate systems (world, virtual, and device), graphics primitives, windows and viewports and metagraphics commands.

Polymer electrolytes for electrochromic window applications

Polymer electrolytes suitable for use in electrochromic window devices for architectural applications have been developed. The electrolyte properties required for a large area, long lifetime, long cycle life and wide temperature range application such as this place some restrictions on the type of polymer system required. The electrolytes developed in this work are based on LiClO 4 in a polyether copolymer which is cured in place to produce a clear elastomer. The material properties and conductivity of electrolytes with and without the plasticizers are presented. Electrochromic device performance tests show that the electrolyte impedance is a factor in the device performance, but not the limiting factor.

AlxGa1−xAs-GaAs-InyGa1−yAs quantum well heterostructure lasers with native oxide current-blocking windows formed on metallized devices

Data are presented demonstrating improved laser operation of AlxGa1−xAs-GaAs-InyGa1−yAs quantum well heterostructures modified with buried native oxide current-blocking windows. The windows are formed by low temperature (425 °C) anisotropic ‘‘wet’’ oxidation of an Al0.9Ga0.1As layer exposed at the facets of metallized laser bars. These window devices operate continuously to powers as high as 248 mW/facet (uncoated, ∼10.5 μm aperture), a ∼25% improvement over nonwindow devices.

PECVD diamond films for use in silicon microstructures

Abstract PECVD techniques have been used to deposit polycrystalline diamond films that have material properties nearly identical to those of natural diamond. Diamond is the hardest known material and has the highest thermal conductivity at room temperature, while the undoped material is an excellent insulator. These and other mechanical, chemical and electrical properties make diamond films attractive for use in applications such as optics, electronic packaging and parts with low wear rates. An X-ray window device has been fabricated using a diamond window and a micromachined silicon substrate.