Blind Angle Research Articles

Joint blind and light control for lighting energy reduction while satisfying light level and anti-glare requirements

This paper presents a joint blind and light control scheme for lighting energy optimization in a lighting control system. The proposed scheme utilizes the maximum available daylight without any glare and reduces lighting energy consumption while satisfying the user’s light level requirements. The optimal blind tilt angle that transmits the maximum available daylight without any glare is computed based on the sun’s altitude and the window ’s orientation, and an optimization problem is formulated that minimizes the required artificial lighting energy to satisfy the user’s lighting requirements. The simulation results show that, relative to conventional lighting control schemes, the proposed scheme achieves improvements in lighting energy consumption while satisfying the anti-glare and user’s light level requirements.

BLIND JOINT ANGLE, FREQUENCY AND POLARIZATION ESTIMATION FOR POLARIZATION SENSITIVE ARRAY USING QUADRILINEAR DECOMPOSITION

This paper links the polarization-sensitive-array parameter estimation problem to the quadrilinear model. Exploiting this link, it derives a blind joint angle, frequency and polarization estimation algorithm. The simulation results reveal that the proposed algorithm has better angle, frequency and polarization estimation performance than ESPRIT. This algorithm relies on a fundamental result of the uniqueness of low-rank four-way data decomposition. Furthermore, the proposed algorithm does not require pairing among multiple parameters. Simulation results illustrate performance of this algorithm.

Transcortical–transforaminal microscopic approach for purely intraventricular craniopharyngioma

Purely intraventricular craniopharyngiomas are rare and pose particular surgical challenges. The two main surgical approaches to these lesions based in the anterior third ventricle are the frontal transventricular approach (through a transcortical or transcallosal approach) and the trans-lamina terminalis approach. The authors note that the pituitary stalk in many of these cases is located in a normal position, which suggests that the third ventricular floor is intact. In such cases, the senior author chooses an approach to avoid disruption of the floor of the third ventricle. Specifically, a traditional frontotemporal approach is not used; we have found that in such cases, a frontal transventricular approach through the usually dilated foramen of Monro provides an optimal visualization of the tumor while minimizing the risks of injury to the hypothalamus and pituitary stalk. The endoscope can be very helpful in exploring blind angles, hidden from the microscopic view. Recognition of this rare location variant of craniopharyngioma is helpful in preoperative planning in an effort to reduce hypothalamic pituitary axis damage. Two patients presenting with craniopharyngiomas that were entirely intraventricular are shown in the video. The patients underwent removal of their tumors without incurring new long-term endocrine deficits. The video can be found here: http://youtu.be/VFlhm_lsrGY. (http://thejns.org/doi/abs/10.3171/2013.V1.FOCUS12347)

LiveMask: A Telepresence Surrogate System with a Face-Shaped Screen for Supporting Nonverbal Communication

We propose a telepresence system with a real human face-shaped screen. This system tracks remote user's face and extracts head motion and face image. The face-shaped screen moves along three degree-of-freedom (DOF) by reflecting user's head gestures. As face-shaped screen is molded based on 3D-shape scan data of user, projected image is accurate even when it is seen from different angles. We expect this system can accurately convey user's nonverbal communication, in particular user's gaze direction in 3D space that is not correctly transmitted by using a 2D screen (which is known as the Mona Lisa effect). To evaluate how this system can contribute to communication, we conducted three experiments. The first one examines blind angle of a face-shaped screen and a flat screen, and compares ease with which users can distinguish facial expressions. The second one evaluates how direction in which remote user's face points can be correctly transmitted. The third experiment evaluates how gaze direction can be correctly transmitted. We found that recognizable angles of face-shaped screen were larger, and that recognition of head directions was better than on a flat 2D screen. More importantly, we found that face-shaped screen accurately conveyed gaze direction, resolving problem of Mona Lisa effect.

Experimental study of convective heat transfer from windows with Venetian blinds

To provide for more detailed and accurate load calculations and energy simulation of buildings, the effect of blinds on convection heat transfer at interior window surfaces was analyzed. Based on full-scale experiments in an office-size chamber for various diffuser locations, window geometry, and blind angles, the study provides convective heat transfer models for natural convection, forced convection due to a ceiling slot diffuser, and forced convection due to a floor register. Results are given in the form of correlations which relate either supply volumetric flow rate or room-surface temperature difference to convection heat transfer at both window and exterior wall surfaces. Results show that heat transfer is dependent on supply flow rate, blind angle, diffuser location and window configuration. Results are compared against previously reported data and show that convection in cases with blinds follows the same form as often arises in turbulent forced convection situations, but differs appreciably in magnitude from previously given models for bare windows. These results should allow for more accurate simulation of energy use in buildings and contribute to the construction of more energy efficient buildings.

Active tectonics in the Malaga Basin: evidences from morphotectonic markers (Western Betic Cordillera, Spain)

The Malaga Basin is located in the westernmost part of the Betic Cordillera. This alpine cordillera in the south of Spain is the most active region of the Iberian Peninsula. Some of the most destructive earthquakes occurred historically in Spain took place within the Malaga Basin. In this work we focus on geomorphic and morphotectonic observations in the aim of finding active tectonic structures that could be seismogenic sources. First, we study the spatial arrangement and age of the Quaternary alluvial fan system as well as the drainage pattern of the basin, followed by the analysis of the distribution of regional markers like marine erosive surfaces and the extend of Pliocene marine deposits in the Malaga Basin. The tectonic structures inferred as active by the morphotectonic analysis are grouped into four main families: N60º-85ºE folds associated with blind thrust faults, N20º-30ºE and N40º-50ºE high angle dip-slip faults, and N165º-170ºE tear faults. Finally, their seismic potential in terms of maximum moment magnitude (Mw) is assessed by means of empirical relationships, varying between 6.0 and 7.0 depending on the hypothesis considered.

Schools of fish and flocks of birds: their shape and internal structure by self-organization.

Models of self-organization have proved useful in revealing what processes may underlie characteristics of swarms. In this study, we review model-based explanations for aspects of the shape and internal structure of groups of fish and of birds travelling undisturbed (without predator threat). Our models attribute specific collective traits to locomotory properties. Fish slow down to avoid collisions and swim at a constant depth, whereas birds fly at low variability of speed and lose altitude during turning. In both the models of fish and birds, the 'bearing angle' to the nearest neighbour emerges as a side-effect of the 'blind angle' behind individuals and when group size becomes larger, temporary subgroups may increase the complexity of group shape and internal structure. We discuss evidence for model-based predictions and provide a list of new predictions to be tested empirically.

Algorithm for blinds control based on the optimization of blind tilt angle using a genetic algorithm and fuzzy logic

This paper presents the calculation of the power of solar rays that pass through the window of an observed room and their impact on warming up and lighting of the room. The calculations were performed using a mathematical model that takes into account the geographical position of the object, time zone, orientation of windows, day of the year, and current time. This paper also includes the calculation of geometry of the solar radiation and its intensity, artificial light and cooling/heating demands. Based on data from above, the optimization of blind tilt angle was performed to achieve the best possible brightness of the room and energy savings when heating or cooling, depending on ambient temperature. Optimization was performed using a genetic algorithm and fuzzy logic. After an analysis of the results obtained from optimization of the blind tilt angle, an algorithm for blinds control was developed in order to achieve energy savings and comfort in the observed room. Based on the derived conclusions, an UML diagram was made that describes the algorithm for determining optimal blind tilt angle.

PARALIND-based blind joint angle and delay estimation for multipath signals with uniform linear array

A novel joint angle and delay estimation (JADE) algorithm for multipath signals, based on the PARAllel profiles with LINear Dependencies (PARALIND) model, is proposed. Capitalizing on the structure property of Vandermonde matrices, PARALIND model is proved to be unique. Angle and delay of multiple rays of sources can be estimated by PARALIND decomposition and an ESPRIT-like shift-invariance technique. Simulation results show that the proposed algorithm outperforms the traditional JADE algorithm. It can automatically distinguish the estimated parameters between sources, and still be available when the number of rays is larger than the number of receiving antennae.

Daylighting and thermal performance of automated split-controlled blinds

Manual blinds are not often adjusted properly. Consequently, electrical lighting as well as heating and cooling loads are increased. The conventional automated control maintains the same blind tilt angle at a particular point in time. An innovative automated split blind system was developed to improve the daylighting and thermal performance of blinds as an integral part of the other building systems. The research objectives were to develop a simplified control method for the split blinds, and to analyze daylighting performance and energy savings due to the application of the split blinds and the control method. A case study that focused on three automated blind systems (conventional (optimum), split (predicted) and split (optimum)) was conducted to analyze the effectiveness of the control methods and the daylighting and thermal performance of the split blinds. Computer simulations were performed using the software EnergyPlus™ to calculate the illuminance levels and glare in a building, and energy consumption as a result of the application of these three blind systems. The simulation results showed that the split blinds (both predicted and optimum) had a better daylighting performance in the back of the room and caused lower energy consumption, especially in winter times when compared to the conventional blinds. An integration of an effective electrical lighting control system is required to fully utilize the advantages of split blinds in summer.

An open-loop venetian blind control to avoid direct sunlight and enhance daylight utilization

Abstract Shading devices, such as venetian blinds, are widely used to eliminate glare and maintain a comfortable working environment for occupants. This paper proposes an open-loop control of blind height and slat angle based on an analytic model of solar position, and geometry of venetian blinds and the windows. The algorithm enables completely blocking direct sunlight from entering the room beyond a certain user specified interior distance from the window while enhancing daylight utilization. We derive closed-form solutions for blind height and angle which are easily implemented in practice. Moreover, the proposed blind control algorithm is simulated with favorable performance. The algorithm has also been implemented and verified in real-time test-beds.

Experimental study of free convection in a window with a heated between-panes blind

An experimental study has been conducted to examine free convection in a window with an enclosed aluminum venetian-type blind. The unique feature of this experiment was that the blind slats were heated electrically to simulate absorbed solar radiation. Convective heat transfer measurements and temperature field visualization were obtained using a Mach–Zehnder laser interferometer. Optical measurements were made for two glazing spacings, two blind slat angles, two blind heat flux levels, and two glazing temperature differences. Both local and average convective heat flux data were obtained in the center region of the tall air-filled enclosure. At the widest glazing spacing, the temperature field was found to be unsteady. For these cases, the temporal fluctuation of the local convective heat transfer was time-averaged using a high speed camera. The experimental results have been compared to a simplified method in the literature for predicting the center-glass heat flux for this configuration.

Study on Judging Direct Sunlight in Actual Use of Blind Slat Angle Control Systems

In a system that automatically adjusts the slat angles of horizontal blinds, it is possible to allow skylight in while shielding direct sunlight. This can lead to good energy savings since it can reduce the need for artificial lighting without increasing the air-conditioning load. Our research has previously demonstrated this effect of reducing the amount of energy consumed by artificial lighting by controlling the blind slats according to the amount of skylight in an existing office building. However, it was confirmed that the occupants were dissatisfied with the system since it controlled the blinds to shut even though the occupants observed no direct sunlight and they could not clearly see out the windows. Therefore, this study was conducted with the aim of setting threshold values between the existence and non-existence of direct sunlight based on daylight conditions, so that the automatic controlling of blind slat angles would be ceased to allow slats open when they do not need to block direct sunlight.

A simplified model of heat transfer at an indoor window glazing surface with a Venetian blind

In this article, a simplified model is developed to predict the radiative and convective heat transfer in a complex fenestration system consisting of a Venetian blind located adjacent to an indoor window glazing. Empirical correlations for natural convection in an asymmetrically heated channel and an isolated flat plate are used in this one-dimensional simplified model. In this simplified model, an energy balance is performed at the blind surface using a mean blind temperature. The radiative heat exchange between the blind, window and room is calculated using a four surface grey-diffuse model, which is coupled to the convective heat transfer. The simplified model has been developed using experimental and numerical data from the literature. Sample results are presented that illustrate the effect of blind slat angle, blind-to-window spacing and absorbed solar heat flux on the heat transfer at the window surface.

Optimization of Photovoltaic Integrated Shading Devices

This study investigated methods of optimizing the operation of photovoltaic (PV) integrated shading devices to attain their maximum benefits to indoor spaces and occupants. A shading device consisting of multiple adjustable louvers coated with PV cells was examined. A motor adjusted the blind angle of the louvers. Sensors measured the available sunlight and daylight levels. The operation of the motor was controlled by a computer based on measured climatic conditions. In developing optimal operation methods, fire energy, thermal, lighting, and visual factors were considered: shading effect, energy production from the PV cells, indoor daylight levels, visual comfort, and thermal comfort. In our control methods, visual comfort supersedes any other physical factors. This is based on the fact that visual comfort is the most important factor in office environments. Thus, it was regarded as the first-order factor in the PV integrated shading control. The performance of a PV integrated louver-type shading device was examined in terms of energy production, light transmission, and visual comfort.

A Beam Switching Planar Yagi-patch Array for Automotive Applications

In this work, a planar beam switching antenna is proposed for wireless commu- nication used in automotive environment. By integrating a Yagi patch antenna array with a one-to-four RF switch, RF power can be delivered to four difierent driven patch elements and generate directive beams toward difierent directions. The prototype antenna is designed to op- erate at the GSM 1800/1900MHz band for cellular phone uses. The size and height of the fabricated antenna are 293mm by 293mm by 3mm, respectively. Measurement results indicate the antenna's gain is approximately 9.478dBi with a 3dB beamwidth of 68 - . 1. INTRODUCTION Due to the rapid growth of wireless communication applications, interference and multi-path fading phenomena become critical and need to be resolved to ensure communication quality. In this paper, a planar beam switching antenna, which is a combination of logic control circuits, a one-to-four RF switch, and Yagi patch antennas (1{5) are proposed to provide spatial diversity. The antenna conflguration is shown in Fig. 1. The Yagi patch comprises four driven patch elements, which are connected via a one-to-four RF switch and flve parasitically coupled director patch elements. By selecting a speciflc through path of the RF switch, RF power is fed to one of the driven patch elements. Because directive radiating elements are used, the antenna can be reconflgured to four difierent beam directions and therefore reduces potential blind angles. Since the antenna comes with a planar structure, it can be employed in the automotive environment. For instance, the planar antenna can be mounted on top of a vehicle. The switching directive beam enables the moving vehicle to track a speciflc base station and extends the communication distance. Such a planar beam switching antenna can also be used for mobile devices to ensure connection quality. The design procedure and geometric parameters of the planar one-to-four beam switching an- tenna are presented in Section 2. The measured antenna performance, including the operational frequency, gain, 3dB beamwidth, and the squint angle, are provided in Section 3. Analysis based on the comparison of simulated and measured results is also given. A brief summary is drawn at the end.

Polarized 3He spin-filters using MEOP for wide-angle polarization analysis

Abstract Polarized 3 He spin-filters are currently employed on a wide range of neutron instruments at the ILL, primarily for diffraction, reflectometry and fundamental physics. A wide range of recent and ongoing improvements are enabling the implementation of this technique for wide-angle polarization analysis for inelastic measurements. These include • Progress in metastability-exchange optical pumping (MEOP), resulting in on-beam polarization levels of up to 80%. • 1st generation “Pastis-1” coils for rotating the neutron polarization at the sample position, allowing for “ XYZ ” polarization analysis. • 2nd generation “Pastis-2” coils with no blind angles in the equatorial plane. • Spin-filter cells with glued silicon windows, allowing for wide-angle “banana” cells with very low background scattering. • Polarization-preserving capillaries for transferring polarized 3 He gas into the cell without manual access. The development of capillary transfer also allows for a completely new way of working with 3 He spin-filters: connecting the cells on the instruments directly to the MEOP filling station several tens of meters away and allowing for quasi-continuous operation.

A theoretical model of shoaling behavior based on a consideration of patterns of overlap among the visual fields of individual members

We propose a hypothetical visual field overlap (VFO) model for shoaling behavior. While solitary individuals have the disadvantage of a substantial blind zone to their rear, the overlapping visual fields among shoal members allows the shoal to collectively view nearly 360°. A highly polarized shoal (i.e., a school) would be less advantageous than randomly oriented shoals because a substantial area blind to all school members (common blind zone) would occur at some distance behind the school. However, in situations where fishes must orient in one direction, the visual fields of individuals in the school overlap such that the common blind zone is considerably farther behind than the blind zone of any particular fish. A simple geometric relationship between school width, the blind angle, and the distance to the common blind zone predicts that larger schools can detect predators at a greater distance than smaller schools. Additionally, the model provides a novel explanation for the nearly universally observed tendency for fish to school together with like-sized individuals. Finally, the effect of school shape on the visual field overlap pattern would have a strong impact on predator–prey interactions. However, our model does not directly take into account the range of visibility or social interaction affects and applies only to small groups. The VFO model suggests that schooling may have arisen as an adaptation to enhance feeding efficiency by reducing the need for individual vigilant behavior while oriented into the current for feeding. We believe the VFO model promises to provide insight into the behavioral ecology of shoaling fishes and that it is highly amenable to both field and laboratory testing.

Angle–Frequency Estimation Using Trilinear Decomposition of the Oversampled Output

This letter links joint angle and frequency estimation problem to the trilinear model and derives a novel blind joint angle and frequency estimation algorithm. Angle and frequency are obtained based on trilinear decomposition of a trilinear model, which is constructed based on oversampling the system output. The proposed algorithm has better performance, and supports small sample sizes. The useful behavior of the proposed algorithm is verified by simulations.

CFD modelling of naturally ventilated double-skin facades with Venetian blinds

This study describes computational fluid dynamics (CFD) modelling of naturally ventilated double-skin facades (DSFs) with Venetian blinds inside the facade cavity. The 2D modelling work investigates the coupled convective, conductive and radiative heat transfer through the DSF system. The angles of the Venetian blind can be adjusted and a series of angles (0°, 30°, 45°, 60° and 80°) have been modelled. The modelling results are compared with the measurements from a section of a prototype-facade testing facility and with predictions from a component-based nodal model. Agreement between the three methods is generally good. It is thought that discrepancies in the results are caused by the simplification of the CFD model resulting in less turbulence mixing within the facade cavity. The CFD simulation output suggests that the presence of the Venetian blinds is able to enhance the natural ventilation flow within the facade cavity and significantly reduce the heat gains to the internal environment. It was also found that the convective heat transfer coefficients on the glazing surfaces are insensitive to the blind angles. The work demonstrated the capability of CFD for modelling complicated heat transfer processes through the DSF system and offered some guidance for CFD practitioners who wish to model similar type of flow.