Window Type Research Articles

An Architecture for On board Frequency Domain Analysis of Launch Vehicle Vibration Signals

The dynamic properties of the airborne structures plays a crucial role in the stability of the vehicle during
 flight. Modal and spectral behaviour of the structures are simulated and analysed. Ground tests are carried out with environmental conditions close to the flight conditions, with some assumptions. Subsequently, based on the flight telemetered data, the on-board mission algorithm and the auto-pilot filter coefficients are fine tuned. An attempt is made in this paper to design a novel architecture for analysing the modal and spectral random vibration signals on-board the flight vehicle and to identify the dominant frequencies. Based on the analysed results, the mission mode algorithm and the filter coefficients can be fine tuned on-board for better effectiveness in control and providing more stability. Three types of windows viz. Hann, Hamming and Blackman-Harris are configured with a generalised equation using FIR filter structure. The overlapping of the input signal data for better inclusiveness of the real-time data is implemented with BRAM. The domain conversion of the data from time domain to frequency domain is carried out with FFT using Radix-2 BF architecture. The FFT output data are processed for calculating the power spectral density. The dominant frequency is identified using the array search method and Goldschmidt algorithm is utilised for the averaging of the PSDs for better precision. The proposed architecture is synthesised, implemented and tested with both Synthetic and doppler signal of 300 Hz spot frequency padded with Gaussian white noise. The results are highly satisfactory in identifying the spot frequency and generating the PSD array.

Climate-zone-dependent applicability of semi-transparent cadmium-telluride-type solar cells as a building material with display characteristics

The applicability of solar signage windows that concurrently generate electricity upon installation in buildings, exhibit display functionality using the generated electricity, and transmit light was evaluated. Four cities representing different US-based climate zones were selected for the analysis: 1A-Miami (Arizona), 2B-Phoenix (Florida), 3C-San Francisco (California), and 5A-Ann Arbor (Michigan). Five types of solar signage windows with different characteristics were designed, and five window-to-wall ratios were considered to analyze the indoor environment and energy consumed by a building by using the DesignBuilder simulation program. The results showed that the solar signage windows were most effective in 3C-San Francisco and least effective in 1A-Miami and 5A-Ann Arbor. According to the amount of electricity generated, an energy-saving rate of up to 17,970 kWh/y (105%) was observed in 3C, highlighting the potential of applying solar signage windows to realize zero-energy buildings in this area. These findings emphasize the remarkable potential of solar signage windows as exterior materials for buildings.

The Effect of Using Tall Windows in Buildings on the Thermal Load of the Building and Its Cost Analysis: A Comparative Case Study for Antalya and Erzurum

The 150 cm tall windows that used as the standard in residential buildings are now being replaced by 220 cm tall windows, which are rapidly becoming widespread. This study examined different window types according to both the type of glass used as well as the type of fill material used in double-glazed windows in order to show the effect of window selection on the energy consumption of the building. A comparison between Antalya and Erzurum was also made in the study. The study was carried out on a building model with seven floors and twenty-four apartments, each of which has five units. The window heights in each unit were assumed to be 150 cm and were defined as Type 0. Five additional building types were defined by increasing the window heights in each unit, respectively. Thermal load values were calculated for all six building types and compared with each other. As a result, a 46.7% increase in the window area causes a maximum heat loss of 9.6% in Erzurum and a maximum heat gain of 45.1% in Antalya. These values bring about an increase in the energy consumption by an average of USD 1465.32 per year in Erzurum and an average of USD 581.08 per year in Antalya.

Grey Wolf algorithmic framework for building energy optimization in India's Köppen-Geiger climatic zones

ABSTRACT Grey Wolf Optimization (GWO) is an emerging evolutionary metaheuristic technique capable of solving challenging engineering problems. Despite its growing popularity, GWO's suitability for building design problems remains unexplored. This paper presents a novel algorithmic framework using EnergyPlus, EPLauncher and Matlab to implement a single and bi-objective GWO for building energy optimization. The goal is to identify optimal wall and window type, orientation, air conditioner's operational profiles and cooling setpoints consistent with minimum annual and peak cooling energy demands for a residential apartment building in five Köppen-Geiger climate zones across India. In place of testing the entire parametric space involving 5,76,000 possibilities, GWO identifies the optimal solutions inside 1250 trials (∼99% run reduction). The single and bi-objective GWO produces (83-97)% and (75-95)% annual and peak cooling demand reductions than a typical construction and operation scenario in the five climate zones. The optimized solutions recommend low thermal transmittance-high capacitance wall sections, 10–15% window-to-wall ratios and double glazed windows with a low solar gain coefficient. Further, optimal air conditioner operational parameters (setpoint and duration) are identified. The presented algorithmic framework is highly robust and can integrate can incorporate upcoming metaheuristic algorithms to perform single and multiobjective building energy optimizations.

기존 주택용 창문 부착형 현열교환 환기장치 제안 및 성능 평가

Purpose: Air pollution is becoming serious around the world, and indoor air quality in buildings is also deteriorating. For energy-saving ventilation and good indoor air environment, this research proposed and made a window type heat exchange ventilation system that can be installed easily in an existing house, and examined its performance. A plate type heat exchange element for ventilator was made by a 3D printer. Method: According to the Korean Industrial Standard KS B 6879:2020 Test Method for Heat Recovery Ventilator, the ventilator was tested four times in a real environment. Two experiments were measured for 10 minutes, and the remaining two were measured for 11 hours and 10 hours, respectively. Ventilation, supply air, exhaust air, and outside air dry-bulb temperatures were measured every 5 seconds. After that, the temperature exchange efficiency was calculated for ventilation, supply air, exhaust air, and outside air average temperature using the temperature exchange efficiency formula described in KS B 6879:2020. Result: The performance was 70.97% in the first experiment, 68.11% in the second experiment, 56.47% in the third experiment, and 64.16% in the fourth experiment.

Survey of window types for aggregation in stream processing systems

In this paper, we present the first comprehensive survey of window types for stream processing systems which have been presented in research and commercial systems. We cover publications from the most relevant conferences, journals, and system whitepapers on stream processing, windowing, and window aggregation which have been published over the last 20 years. For each window type, we provide detailed specifications, formal notations, synonyms, and use-case examples. We classify each window type according to categories that have been proposed in literature and describe the out-of-order processing. In addition, we examine academic, commercial, and open-source systems with respect to the window types that they support. Our survey offers a comprehensive overview that may serve as a guideline for the development of stream processing systems, window aggregation techniques, and frameworks that support a variety of window types.

Determination of Harmonic Parameters in Pathological Voices—Efficient Algorithm

The harmonic parameters Autocorrelation, Harmonic to Noise Ratio (HNR), and Noise to Harmonic Ratio are related to vocal quality, providing alternative measures of the harmonic energy of a speech signal. They will be used as input resources for an intelligent medical decision support system for the diagnosis of speech pathology. An efficient algorithm is important when implementing it on low-power devices. This article presents an algorithm that determines these parameters by optimizing the window type and length. The method used comparatively analyzes the values of the algorithm, with different combinations of window and size and a reference value. Hamming, Hanning, and Blackman windows with lengths of 3, 6, 12, and 24 glottal cycles and various sampling frequencies were investigated. As a result, we present an efficient algorithm that determines the parameters using the Hanning window with a length of six glottal cycles. The mean difference of Autocorrelation is less than 0.004, and that of HNR is less than 0.42 dB. In conclusion, this algorithm allows extraction of the parameters close to the reference values. In Autocorrelation, there are no significant effects of sampling frequency. However, it should be used cautiously for HNR with lower sampling rates.

Pickup and delivery with lockers

We define a pickup and delivery routing problem with time windows that arises in last-mile delivery. A customer can be served either directly at home, by one of the available capacitated trucks, or via lockers, that allow a self-service option. On the same route, the couriers must deliver the parcels and collect the packages that the customers intend to return. The returned parcels can be picked up directly at the customers’ homes or at a locker. Customers can select home service, self-service at one of the nearby lockers with a discount, or let the logistics company decide. All services must be performed within a given time window.We propose three formulations, two branch-and-cut algorithms, and some valid inequalities. We also investigate the case with a single vehicle, with different types of time windows, including no time windows. Moreover, we show how to accommodate simultaneous pickup and delivery and multiple requests from a customer.

A Comparative Study on Smart Windows Focusing on Climate-Based Energy Performance and Users’ Comfort Attributes

A facade can control interaction between the building and the environment. Advancements in control technologies and material science give the opportunity of using smart windows in a high-performance facade to improve the building’s energy performance and users’ comfort. This study aims to propose practical recommendations for smart windows’ implementation over various climate zones across the world. To follow this aim, 54 studies published from 2013 to 2022 collected from architecture, engineering, and material science databases and have been reviewed, and seven types of smart windows including electrochromic, photovoltachromic, gasochromic, thermochromic, photochromic, hydrochromic, and Low-E have been identified. Moreover, the thermal properties and visual features of smart coatings used in the windows and their impacts on energy efficiency and users’ comfort were recognized. Then, a comparative study was conducted to identify and propose the most efficient coating utilized in the structure of smart windows across different climate zones.

A model study of low-frequency noise exposure indoors due to road traffic

Indoor low-frequency noise levels due to road traffic has been modelled for facade examples consisting of a lightweight steel facade, a concrete facade and two types of windows. Possible audibility of heavy vehicles passing by has been investigated as well as the dependence of the exposure level on driving speed and distance to road. The results show that pass-by events may be audible at low frequencies for cases complying with building standards and noise guideline values exemplified by Swedish regulation. Moreover, the A-weighted levels may be dominated by low frequency noise, and the frequency of occurrence of pass-by traffic noise events may be sufficiently high to create disturbance for typical traffic situations. Furthermore, it is shown that the contribution of pass-by events to the equivalent level indoors may increase when the driving speed is lowered.

Automated Hypertension Detection Using ConvMixer and Spectrogram Techniques with Ballistocardiograph Signals.

Blood pressure is the pressure exerted by the blood in the veins against the walls of the veins. If this value is above normal levels, it is known as high blood pressure (HBP) or hypertension (HPT). This health problem which often referred to as the "silent killer" reduces the quality of life and causes severe damage to many body parts in various ways. Besides, its mortality rate is very high. Hence, rapid and effective diagnosis of this health problem is crucial. In this study, an automatic diagnosis of HPT has been proposed using ballistocardiography (BCG) signals. The BCG signals were transformed to the time-frequency domain using the spectrogram method. While creating the spectrogram images, parameters such as window type, window length, overlapping rate, and fast Fourier transform size were adjusted. Then, these images were classified using ConvMixer architecture, similar to vision transformers (ViT) and multi-layer perceptron (MLP)-mixer structures, which have attracted a lot of attention. Its performance was compared with classical architectures such as ResNet18 and ResNet50. The results obtained showed that the ConvMixer structure gave very successful results and a very short operation time. Our proposed model has obtained an accuracy of 98.14%, 98.79%, and 97.69% for the ResNet18, ResNet50, and ConvMixer architectures, respectively. In addition, it has been observed that the processing time of the ConvMixer architecture is relatively short compared to these two architectures.

Simulation of performance of five types of external windows: a case study in Chongqing, China

The efficiency of transparent envelopes must be improved in purpose of saving energy. The EnergyPlus software was used to examine the inside glass surface temperature and annual energy performance (AEP) of five different types of external windows, including built-in louvre ventilation windows (BLVW), built-in louvre hollow windows (BLHW), interior side louvre ventilation windows (ILVW), ventilation windows (VW), and regular hollow windows (HW), using office buildings in Chongqing as the target. The results demonstrate that the design of ventilation and louvres can reduce energy consumption of buildings, lower the room's radiant asymmetry, and raise occupant thermal comfort. During the cooling season, built-in louvre ventilation windows and hollow windows for rooms facing south are the best window operation options. During the heating season, ventilation windows are the best option. In four orientations of north, east, south, and west, respectively, the overall building energy efficiency rate of the optimal operation mode compared to typical hollow windows is 5.87%, 5.70%, 2.80%, and 5.74%. This will serve as a guide for the building design of energy-efficient windows and the mode of the windows' year-round functioning in Chongqing.

Study on the Influence of Window Type on Natural Ventilation Effect Based on CFD Simulation

Good natural ventilation is one of the basic conditions for people to be able to work and live indoors. In this paper, wind velocity, wind velocity non-uniformity coefficient and air age are taken as the evaluation indexes of indoor ventilation condition. A simulation software Airpak is used to build room models with three window types (with the same ventilation area), namely, top-hung window, casement window and sliding window. The wind incidence angle was adjusted between 0°- 90°, and the indoor wind velocity and air age of the room were simulated when the casement window was opened at 90°, the sliding window was fully opened and the top-hung window was opened at 30°. The average wind velocity, wind velocity non-uniformity coefficient and air age of the room under each working condition were calculated and analyzed to evaluate the freshness and comfort of the indoor air, so as to provide guidance for the reasonable design of indoor layout.

EVALUATING THE EFFECT OF MASHRABIYA AND PERFORATED MALAY CARVING WINDOW ON THE INDOOR NATURAL VENTILATION PERFORMANCE OF LIVING SPACE

This study focuses on natural cross-ventilation improvements in terms of internal air velocity, measured in meter per second in the living room space in Malaysia, using two types of perforated windows namely, Mashrabiya window as well as perforated Malay carving window element to determine the performance of their internal air velocity. Cross ventilation has been proposed as one of the most effective natural ventilation methods for thermal comfort by several studies. It is, however, one of the most misunderstood aspects of passive design's approach to regulating interior temperature. In this study, the proposed design solution is by introducing the Mashrabiya (W1) and perforated Malay carving window (W2) as two predominant indigenous solutions for traditional houses that can be further developed and utilized in modern houses. The research involves three stages. The first stage includes the inventory exercise on five (5) different reference case studies of perforated windows. This is to ascertain the most fundamental and common pattern, as well as the dimensions of each W1 and W2. The second step involves computer simulations utilising Computational Fluid Dynamics (CFD) software known as Ansys fluent R2 2021. This program is used to simulate and evaluate natural air velocity and its performance in an interior context, and to determine the viability of a recommended design solution. Finally, an empirical method is used to predict the internal air velocity. The result shows that W1 and W2 represent effective passive design strategies for energy saving. The air velocity using W1 is three times higher than the normal speed which is 4.5/1.5 m/s, while using W2 makes the air velocity two times higher than the actual air speed which is 3/1.5 m/s. The simulation test and results are discussed based on the Malaysian region with a 1.5m/s wind speed. Understanding the different effects of the size of the voids and the placement of the patterns are significant to improve the indoor natural ventilation performance in a living room space.

Regulation, Competition, and Information

You know it is very hard after the Governor, State Bank, to make a presentation but I will try to do it in a very mundane way. You know the Regulatory Bodies specially in the Economic Sector in recent times. There has been a sort of resurgence, leaving aside the regulation of the financial sector, which has been doing very well. Our old memory of regulation is not so pleasant. Long ago, there used to be a transport Authority which used to dole out “Route Permits” as political favours, and there was you know fixation of Bus Fares not always based on economic considerations but based on arbitrariness. But luckily we have learnt a lot. First, we learnt that it is good to deregulate and I think the primary purpose of the present resurgence is to deregulate. You have a regulatory body to deregulate. Secondly as the finance Minister said yesterday himself that this is a new paradigm. The regulation now has a major ingredient of a development role and in Pakistan with the combination of licencing as necessary part of regulation, you are very effective in that role and it also genuinely provides an opportunity for a one window type of operation where you give a permission and you facilitate the type approvals and then you help them dealing with the local agencies. Although you have brief period for evaluation but the preliminary perception is that they are fairing better than our Industrial Development Corporations which were given the role to promote the Private Sector.

Energy efficient glazing: A comparison of microalgae photobioreactor and Iranian Orosi window designs

Orosi is a traditional Iranian window which is made of colorful glasses embedded in wooden latticed frame. This window was designed in traditional courtyard houses located in central Iran and behaved as a passive strategy to control light intensity, provide privacy and aesthetics. However, this type of window is rarely used nowadays due to a lack of acoustic and thermal insulation and high construction costs. This paper explores the possibility of using double-glazed window with colored microalgae inspired by Orosi to improve its light performance and energy consumption compared to the traditional Orosi window design A series of experimental tests and a set of computer simulations are conducted to evaluate and compare the two designs. The experimental results showed that while the light intensity in the indoor space is approximately equal to the corresponding magnitude measured for the Orosi window, the inside temperature witnessed a small increase approximately 1° Celsuis. Likewise, relative humidity, which has a significant impact on thermal comfort perceived by occupants, increased from 25% to nearly 70% in the algae window. Based on results obtained, nearly 500 ppm of CO2 was absorbed due to the low height of the photobioreactor. Results of computer simulations indicated that the amount of annual energy consumption in terms of cooling electric energy, heating fuel energy and electric equipment within the two simulated models were similar. However, the best performance of the colored algae window in terms of UDI was observed when the microalgae concentration was between 40% and 50%.

Novel system using hydrogel with reduced graphite oxide particles as active layer for potential application in smart window

A suspended particle device (SPD) is a type of smart window that can be switched with an electrical stimulus, and its transmittance varies proportionally with the applied voltage. This work presents a new route to produce SPD, using hydrogels based on conventional polymers with trapped reduced graphite oxide (rGO) micrometric particles as an active layer, to make this product more accessible, as it is not yet cost-effective. The trapped rGO particles were produced from the chemical oxidation of graphite, followed by thermal reduction. The results of X-ray photoelectron spectroscopy (XPS) confirmed the production of reduced graphite oxide particles with a low quantity of oxidized carbon groups. X-ray diffraction (XRD) showed the crystalline graphitic structure of the produced rGO particles and proved their incorporation inside the hydrogel's tridimensional polymeric network. The presence of these particles causes a decrease of 28.3% in the degree of swelling of the hydrogel. The devices were assembled in two different configurations: (i) fluorine-doped tin oxide (cFTO); and (ii) silver paint (cAg) by changing the positions of the electrodes. The cAg device displayed better responses, with an immediate increase of 38.6% in transmittance, due to an applied voltage of 220 V, compared to the switched-off device. The voltage applying time also increased the transmittance of the cAg device, with an increase of 36.6% after 20 min under 220 V, compared to the device immediately turned on.

Multi-Objective Optimization of Ultra-Low Energy Consumption Buildings in Severely Cold Regions Considering Life Cycle Performance

Net-zero energy buildings (NZEB) have received widespread attention for their excellent energy and carbon reduction potential in various countries. However, relatively little research has been conducted on the life performance of its primary form: the ultra-low energy building (ULEB). This paper proposes an optimization method combining meta-models to investigate the carbon reduction potential of ultra-low energy buildings in severely cold regions of China. The XGBoost algorithm is used to construct a meta-model of building performance, and the grid search method is used to obtain a high-precision meta-model with an R2 of 0.967. Secondly, NSGA-II is used to find passive technical solutions based on the meta-model that minimize the global warming potential (GWP), global cost (GC), and operation energy consumption (OE). Finally, the variables affecting the life-cycle performance of buildings were ranked by sensitivity analysis. The results show that GWP, GC, and OE are reduced by 12.7%, 6.7%, and 7.4% compared with the original building through the optimization process proposed. Sensitivity analysis showed that for GWP, the top four sensitivities are window type (TW) > WWR of south wall (WWRS) > roof insulation thickness (IR) > WWR of north wall (WWRN). For GC, the top four sensitivities are: TW > WWRS > IR > WWR of west wall (WWRW); for OE, the top four sensitivities are: TW > IR > WWRS > WWRN. This paper’s optimization framework and research results can effectively guide the design of the ULEB in severely cold regions.

Optimize temporal configuration for motor imagery-based multiclass performance and its relationship with subject-specific frequency

Enhancing the performance of motor imagery-based Brain-Computer Interfaces (BCI) has been a significant goal in the BCI field. To achieve such a goal, several typical and promising techniques have been implemented, such as developing intelligent algorithms, combining features from different domains, extracting subject-specific parameters, and so forth. Previous studies performing temporal segmentation often ended up with a large number of features and placed a burden on computational cost, which poses a disadvantage to online analysis. This study proposes a novel approach to utilizing short-window segments to find an optimal combination of time segments and feature extractors. Electroencephalogram data from four datasets (BCI Competition IV dataset 2a, 2b and two self-acquired datasets) were segmented into four types of the time window and had features extracted by Common Spatial Pattern and its variants, and lastly classified by Linear Discriminant Analysis. The result shows that the combination of the “2-s with 1-s overlapping” segment and Filter Bank Common Spatial Pattern yields overall accuracy of 2–6.5% (p-value <0.05), higher than other methods in comparison. In addition, the study finds that there is a negative correlation (r = −0.38) between the number of subject-specific frequency bands and the performance (p-value <0.0001). The results demonstrate that the narrower and more focus frequency range chosen, the more accurate the model can achieve. Our results indicate that the “2-s with 1-s overlapping” segment would be an ideal candidate for online BCI analysis, and the response of selected frequency bands could be an informative indicator to evaluate BCI performance.

Simulation framework for early design guidance of urban streets to improve outdoor thermal comfort and building energy efficiency in summer

Global warming and the urban heat island effect have led to the deterioration of the outdoor thermal environment and the rise of building cooling demand, calling for urban design with high environmental quality. However, little has been changed in the practice of urban street design. This paper bridges this gap by developing a framework of parametric simulation for design guidance of urban streets with an advanced urban canopy model that can simulate the interactive indoor-outdoor environment. Case studies are conducted at the neighborhood scale for six cities to improve outdoor thermal comfort and building energy efficiency in summer. The influence of street and building design parameters has been investigated based on 31104 simulations. Results reveal the conflict between optimizing outdoor thermal comfort and optimizing building energy efficiency. In the majority of the investigated cities, window-to-wall ratio, window type, and street orientation are the most influential parameters. Strategies by adjusting these parameters can significantly improve outdoor thermal comfort, as quantified by thermal stress hours, at a cost of increasing the building cooling load. Planting bigger and denser roadside trees always moderately reduces the thermal stress hours and building cooling load. These results demonstrate the potential of this framework to identify the design trade-offs between thermal comfort and building energy efficiency. The framework can be extended to various cities to help designers and policymakers at the early design stage.