Comfort Limits Research Articles

The essential properties governing the appropriate selection of phase change materials integrated into heavy structure buildings

This paper examines the essential properties governing the appropriate selection of phase change materials (PCMs) integrated into heavy structure buildings during different seasons. Nine PCMs with various thermophysical properties were evaluated, in the free-floating mode, under hot and dry climate conditions. The practical examined range of each property is extracted from the data of the nine considered PCMs. An indoor experiment was designed and constructed to validate the simulation models created with the EnergyPlus and Designbuilder building simulation programs. The results confirm that the large latent heat of fusion and low thermal conductivity of PCMs enhance the indoor thermal comfort at the same melting temperature. The Intensity of Thermal Discomfort (ITD) decreases from 51 to 36.4% as the energy density increases from 138.6 to 180.6 MJ/m3, for two PCMs with a melting temperature of 21 °C. As the PCM melting temperature increased from 21 to 29 °C, the ITD index decreased from 27 to 10 °C.day. Thus, the occupants’ thermal comfort enhances as the PCM melting temperature approaches the upper limit of the adaptive thermal comfort. In brief, the ITD sensitivity index (the relative change in ITD due to a relative change in PCM property) is highly affected by the PCM melting temperature (5.85), followed by latent heat (1.37), density (0.71), thermal conductivity (0.41), and the phase transition region (0.096) that has a negligible effect on the indoor thermal comfort.

NEUROMARKETING AS A TOOL FOR THE ANALYSIS OF VISUAL COMFORT OF ARTIFICIAL LIGHTING IN PUBLIC SPACES

Currently, most large cities in developed economies are developing and implementing master plans for night lighting. A comparative analysis of 14 master plans unequivocally indicates that the visual comfort of night lighting of open public spaces is one of the most important functions of the organization of the urban environment. However, it should be noted that the understanding of visual comfort in all analyzed works has a very subjective nature and is based on the personal experience and aesthetic preferences of architects. The author has developed a new approach to the analysis of the visual comfort of night lighting. This approach is based on presenting the perception of the visible environment as a step-by-step process of visual perception of the environment by a person. There are three stages of perception in total, namely: psychophysiological level (stage) of perception, emotional-aesthetic and visual-artistic. This article examines the prospects of using the neuromarketing paradigm as a tool for assessing the emotional (emotional-aesthetic level of perception) reactions of recipients to the night lighting of open public spaces. Based on the above, it became possible to determine the emotional and aesthetic limits of the visual comfort of the architectural environment, which in the study are reduced to three main functions of visual comfort: Compensatory (protective) - helps a person in the process of perceiving the aesthetics of the environment to restore internal emotional harmony; Integrating (that unites) - creates a feeling of harmony, integrity and involvement in the environment in human perception; Hedonistic - forms satisfaction from the aesthetic qualities of the architectural environment. Each of the listed functions of comfortable perception of artificial lighting of open public spaces is evaluated according to two groups of characteristics: color and brightness of light. Measurement of physiological and neural signals helps in the creation of creative design, development of emotionally attractive lighting projects, detection of depressive zones and in other areas of architectural activity. Brain scans that measure its neural activity and tracking physiological responses (eg eye saccades, pressure changes, breathing rate, etc.) are the most common measurement methods. Neuromarketing tools can become the basis for identifying quantitative parameters of emotional reactions of target population groups to the visual qualities of lighting in public spaces. Keywords: visual comfort, function of visual comfort, neuromarketing, architecture, emotional and aesthetic level of perception.

Role of temporary thermostat adjustments as a fast, low-cost measure in reducing energy imports

Efforts to combat climate change involve long-term plans to reduce the energy demand and increase the share of locally generated renewable energy. However, a sudden change in the geopolitical situation may require an even more rapid response to reduce energy imports through energy-efficiency improvements. In the building sector, retrofits to the building envelope and heating systems are effective, yet time- and cost-intensive to improve energy efficiency. A fast, low-cost measure to address this need is to lower the temperature set-points in building heating systems to within comfortable limits. Here, we show the impact of reducing the temperature set-point by 1 °C on heating demand at different scales—building, regional, and national—using demand simulation of 240 Swiss building archetypes and clustering-based upscaling methods. We demonstrate a nearly 6% reduction in the residential space heating demand at the national level, about a third of which is met with natural gas. More importantly, the presented approach highlights potential implications of the proposed measure across a national residential building stock, considering differences in climate and building archetypes, as well as their spatial distribution.

Impact of climate change on sustainable production of sherry wine in nearly-zero energy buildings

Wine is the main economic resource in the ‘Area of Jerez’, located in the south of Spain. It is one of the most important wine tourism destinations in the world. However, its sustainable production process, so strongly influenced by climatic conditions, can be clearly affected by the phenomenon of global warming. The ageing process of “Sherry wine” takes place in buildings known as ‘Cathedral warehouses’, an example of Nearly-Zero Energy Buildings (NZEBs). For centuries, they have been used to provide specific ecological conditions for biological ageing without any type of mechanical heating/cooling system. The purpose of this paper is to assess the impact of climate change on this production model. For this, the annual thermal behavior of a representative winery was monitored during several years. The first energy simulation model of this type of buildings was developed and validated (daily R2 = 99%; hourly R2 = 97%). Finally, the model was simulated by modifying the outdoor climatic conditions (9 years training data sets) for a climate change scenario, applying the ‘morphing’ method for the transformation of the weather data. The results show that, by the middle of this century, the average outdoor temperature will increase by 2.3 °C (in summer up to 3.6 °C). As a consequence, the temperature in the ageing zone would exceed the comfort limit for 19% of the year, (up to 34% in hot years). For 2080, the prediction is even worse (average value of 27%). As a result, the microorganisms responsible for this unique process could not maintain their activity. This fact will force the sector to face a harsh reconversion through the adoption of new mechanisms and strategies, which endangers the economic sustainability of an entire region dedicated to this practice. Beyond the specific case, the work highlights the need to evaluate the future behavior of NZEBs through simulation.

Evaluation of the thermal performance of traditional courtyard houses in a warm humid climate: Colima, Mexico

With the recent need to decrease energy use and promote indoor thermal comfort in overheating conditions, attention has been drawn to the passive cooling function of courtyards. This paper aims to determine the effect of proportions and orientations of courtyards on the indoor thermal performance of traditional houses in a warm, humid region so that this could guide further improvement and reinterpretation of this building type. The results of this parametric study were obtained through computer simulations of different cases with the aim to determine the influence of orientation, courtyard size and proportions on the indoor thermal energy balance and thermal comfort of a traditional building in a warm-humid region. Rather than promote passive cooling in the building, the findings suggest that the courtyard greatly increases solar heat gain, raising the temperature during the day. Higher solar heat gains and ventilation rates were observed in the courtyard cases with greater width and length. Nevertheless, this does not cause important differences in the average operative temperature of the entire building between the cases. As for orientation, lower heat gains were obtained in courtyards with the long axis-oriented east to west. Regardless of the cases, the study finally emphasizes the importance of the inhabitants controlling the opening of windows in the enclosed rooms since this could decrease the temperature by 1.1 °C from night to the early morning (23.00 hrs to 11.00hrs) and thus influence its thermal comfort. Conversely, opening the windows outside that time-lapse could cause an increase in temperature and more hours above the upper comfort limit.

The week that will be: Communicating the impact of climate change via extreme weeks

As events like the 2003 European heatwave showed (where 14,000 people died in Paris alone), it is in the extremes of weather, not the mean climate, where much climate change risk lies. Communication with the public, or the testing of natural and human-made environments via simulation, has focused however on the mean situation. To many, a future 2 or even 4 °C rise in mean temperature will seem modest and hence fail to convey the scale of the issue, thereby creating a gap between reality and expectation. Here we use the idea of presenting an audience with a week-long time series of future local extreme weather as a way of bridging this gap. A week has both vernacular currency and covers the length of many heatwaves. We generate UK future weeks in 2030, 2050 and 2080 at a 5 km interval, thereby allowing interested parties to visualise for the first time likely future heatwaves in their locality. Future heatwaves of similar form as the 2003 Paris event are found, but with even higher temperatures, suggesting the likelihood of largescale mortality. We apply the approach to the conditions within a UK home under future heatwaves with return periods of 10–50 years. Conditions far beyond adaptive comfort limits are found. Weather files containing the extreme weeks for 11,326 locations have been prepared and are made available. These will be of use to those trying to explain the likely impacts of climate change, governments setting resilience policy and those using computer modelling.

Dynamic Motions of Piled Floating Pontoons Due to Boat Wake and Their Impact on Postural Stability and Safety

Piled floating pontoons are public access structures that provide a link between land and sea. Despite floating pontoons being frequented by the public, there is limited data available to coastal or maritime engineers detailing the dynamic motions (acceleration and rotation) of these structures under wave action and the impact of these motions on public comfort and safety to inform their design. This contribution summarises results from a set of laboratory-scale physical model experiments of two varying beam width piled floating pontoons subjected to boat wake conditions. Observed accelerations and roll angles were dependent on beam-to-wavelength ratio (B/L), with the most adverse motion response observed for B/L ~0.5. Internal mass of the pontoon played a secondary role, with larger mass structures experiencing lower accelerations for similar B/L ratios. Importantly, these new experimental results reveal the complex interaction between the piles and pontoon that result in peak accelerations more than six times the nominated operational safe motion limit of 0.1g. Root mean square (RMS) accelerations were more than three times the nominated comfort limit (0.02g) and angles of rotation more than double what would be perceived as safe (6 degrees) for the boat wake conditions tested. The frequency of acceleration also suggests patrons standing on these platforms are likely to experience discomfort and instability. Laboratory results are compared against a series of field-scale experiments of pontoon motion response and patron feedback. The dynamic motion response of pontoons tested in both field-scale and laboratory experiments compared well.

Performance Optimization by Adaptive Control of Material Properties in Portable Electronic Devices

We evaluate the potential benefits of using tunable material properties within portable electronic devices for increasing the total power generated across different operating scenarios. In these devices, in addition to the die temperature limits, the user-exposed device skin must be kept within ergonomic comfort limits, requiring adaptive control to balance these constraints. Present thermal management strategies rely on control of the allowed amount of heat generation (performance throttling) to maintain the die and skin temperatures within permissible limits as the operating conditions fluctuate. To address this drawback, we investigate the performance benefits offered by integration of material layers into a representative device that could adaptively control their properties, so as to maximize the heat dissipation while preserving the junction and skin temperatures within prescribed bounds. A steady-state model is employed to identify the required thermal conductivity of the tunable material layers that maximize the device performance. The model predicts that tunable materials could offer a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim 15$ </tex-math></inline-formula> %–20% increase in the maximum power that can be dissipated, due to modulation of the junction-to-skin thermal resistance, for a representative platform and range of operating conditions. We demonstrate a case study to understand the effect of introduction of the tunable material on the junction temperature at the peak power dissipation, considering the same upper and lower bounds of thermal conductivity for different device form factors. In summary, the work critically identifies the need for target material properties required to achieve this optimal performance with realistic and modest tuning ratios of the effective material conductivity, which can be used to target future materials development and controls strategies for this application.

Empirical evaluation of demand side response trials in UK dwellings with smart low carbon technologies

Low carbon technologies along with smart control have a role in residential demand side response (DSR) to shift the timing of household energy consumption away from peak times and align it with generation of renewable electricity. This paper empirically evaluates the impact of DSR trials on grid electricity import and resident experience regarding disruption to daily routines, thermal comfort and noise disturbance in 17 thermally efficient social housing dwellings (Barnsley, England). Four types of DSR trials were run through 22 interventions performed in March to April 2021. Each dwelling was equipped with a 5 kWh electro-chemical battery and air source heat pump, and all but one dwelling had solar photovoltaic (PV) panels (1.3–3.0 kWp). Interventions were applied against a flat (single) rate tariff as well as dynamic time-of-use tariffs. On average, secure turn-down interventions between 5 and 7 p.m. resulted in a reduction in grid electricity import of 1.2 kWh per household and a reduction in controllable load (heat pump plus battery energy) of 3.7 kWh per household. The batteries enabled 2.5 kWh per household of electricity to be exported to the grid for these interventions. On average, turn-up interventions between 1 and 3 p.m. resulted in an increase of 2.3 kWh per household in grid electricity import. Individual dwellings showed different levels of demand response depending on the levels and patterns of household electricity consumption.The resident experience was evaluated by means of a series of telephone surveys. Householders were generally accepting of the trials in terms of changes in indoor temperature, hot water availability, noise disturbance and disruption to household routines. However, some general concerns were raised about the energy systems relating to indoor temperature, hot water temperature and energy costs. The general acceptability of automated DSR, conditional on thermal comfort limits and manual override, is promising for the wider application of residential DSR driven by price signals, although ongoing household engagement in DSR schemes will require a continued focus on the householder experience with training and support in using new technologies. A routine period of inspection should be employed to identify any issues with energy system issues ahead of DSR initiation.

Learning and Learners’ Inability to Learn a Foreign Language

Learning is the long-term changes in the individual's behaviour due to experiences. For knowledge and skill to be considered learning, there must be a change in the individual's behaviour, and this change must continue. In this case, repetition is important for learning to become permanent. There are some major issues that students should pay attention to while trying to learn a foreign language. Some are directly related to each other and can be named as lack of motivation, staying within the comfort limits, long vacations, not repeating, and not prioritizing needs. In this study, the most obvious factors affecting the learning of foreign language learners were determined, and it was emphasized what to pay attention to in the learning process.

A Preliminary Study on Vibration Response of Profiled Steel Sheet Dry Board (PSSDB) System under Heel-drop Test

This paper aims to evaluate the vibration response of the profiled steel sheet dry board (PSSDB) composite system under heel-drop test. Three (3) specimens with dimensions of 840mm width and 2000mm length were prepared. The specimen consists of a sample without concrete infill (P45HL), foamed concrete as infill (P45FC), and normal concrete as infill (P45NC) material. The specimen was erected using profiled steel sheet (PSS), 1mm thickness, and connected to a dry board (DB), 16mm thickness using self-drilling screws at 200mm screw spacing along the longitudinal direction. A heel-drop test was conducted, and modal analysis was performed using MEscope software. The FRF measurement was carried out using accelerometers, and the time-domain measured responses were converted to FRF to acquire modal characteristics such as natural frequency and mode shape of the structures. The natural frequency of the first mode shape is 17.7Hz, 14.2Hz, and 4.5Hz respectively for specimen P45H, P45FC, and P45NC. It demonstrates that the natural frequency of the specimen without infill and foamed concrete as infill is more than the human comfort limit value of 8Hz, implying that P45HL and P45FC will be comfortable for building occupants.

Placing of the second oldest red ochre mine in mainland Europe, Lovas, Hungary, to human, paleoenvironmental and paleobiogeographic context

Although the 13.2–13.8 ky old Lovas red ochre mine, Central Transdanubia, Hungary is a very important Upper Palaeolithic archaeological site being the second oldest in mainland Europe, we have little knowledge of the conditions under which and how long the pits were cultivated and the post-mining sedimentation processes. The aim of the study was to study certain human circumstances of the mining activities, reveal the former ecological conditions which influenced the sedimentation processes and investigate how the changing climatic conditions led to the formation of the fossil macrofaunal assemblage of the archaeological site. The removal of ca. 25 m3 of pigment material from the pits was equivalent to a maximum of 8750–11042 transport occasions per person, although the pre-transport processing of the material could notably reduce the weight of the transportable pigment and the time demand. Based on the lower thermal comfort limit, mining activities could be performed predominantly in the summer months. In the relatively humid Bølling-Allerød period, the redeposition of the excavated barren material to the cavity could be rapid after the termination of the mining activity. In the Younger Dryas Stadial and the early Holocene, the recharge and covering of the former pits with sediment could be slow and it started to increase only in the mid-Holocene period. The modelling of the potential distribution range of five macrofaunal elements indicates that all the species occurred at the site in the Bølling-Allerød period in the wider environment of the Lovas red ochre mine. The reconstructed boreal forest biome in the time of cultivation of the mine can explain well the dominance of fossil elk bones found in the fossil assemblage.

Indoor air quality, thermal comfort and ventilation in deep energy retrofitted Irish dwellings

Residential building stock energy retrofits will play a key role in EU climate actions. The impact of these retrofits on indoor air quality (IAQ) and occupant comfort needs to be assessed to inform future renovation programmes. This study evaluated IAQ and occupant satisfaction in a sample (n = 14) of deep energy retrofitted Irish residences, at least 12 months post retrofit. Measurements of PM2.5, formaldehyde, total volatile organic compounds (TVOCs), carbon monoxide, radon, and carbon dioxide were made in the main bedroom and living area over a period of two days to three months (depending on the pollutant). Temperature and humidity in most homes were within design comfort limits. Higher concentrations of all pollutants were measured in bedrooms. Only 30% of bedroom data met EN16798 Category I limits for CO2 (within 380 ppm of outdoor concentrations), suggesting that bedrooms maybe under ventilated. Median formaldehyde concentrations of 25.4 and 20.7 μg/m3 were detected in bedroom and living rooms respectively, with building materials likely being the major source. All radon data (apart from one home located in a high radon area) was less than the national reference value of 200 Bq/m3. Measured ventilation extract flow rates in most participating homes would not meet the minimum performance requirements in Irish Regulations of 2019 – introduced post completion of the retrofits in this study. Greater compliance with the ventilation requirements of retrofits and the promotion and use of low emitting construction materials are recommended.

Thermal comfort evaluation in architectural studio classrooms – A summer study in a warm to moderate Indian climate

This paper reports the findings from a thermal comfort field study conducted in institutional studio classrooms in the warm-to-moderate climate of Tumkur in Karnataka, India. A total of 506 datasets were obtained in the questionnaire survey consisting of students of architecture. The survey was carried out during the hot-dry months of March, April and May 2019 using subjective questionnaires during which indoor environment variables were measured simultaneously in accordance with ASHRAE Standard 55 Class II protocols. A comfort temperature of 30.4°C was obtained using Griffith’s method, and the comfort band was found to be between 25.0°C to 32.5°C on the central sensation scale for 80% acceptability for the summer (hot-dry) season. Subjects showed greater tolerance and adaptation to warmer conditions with the main means of adaptation by opening windows, wearing lighter clothing, use of ceiling fans, drinking of cold water and use of curtain blinds. Comparison of the field study results with international standards shows that the standards failed to capture the comfort limits and adaptations of subjects in tropical climates of India. Findings of the present study bear significance in developing guidelines for thermal comfort for institutional buildings in the warm-to-moderate climate of India.

Surface Electromyography as a Natural Human–Machine Interface: A Review

Surface electromyography (sEMG) is a non-invasive method of measuring neuromuscular potentials generated when the brain instructs the body to perform both fine and coarse locomotion. This technique has seen extensive investigation over the last two decades, with significant advances in both the hardware and signal processing methods used to collect and analyze sEMG signals. While early work focused mainly on medical applications, there has been growing interest in utilizing sEMG as a sensing modality to enable next-generation, high-bandwidth, and natural human-machine interfaces. In the first part of this review, we briefly overview the human skeletomuscular physiology that gives rise to sEMG signals followed by a review of developments in sEMG acquisition hardware. Special attention is paid towards the fidelity of these devices as well as form factor, as recent advances have pushed the limits of user comfort and high-bandwidth acquisition. In the second half of the article, we explore work quantifying the information content of natural human gestures and then review the various signal processing and machine learning methods developed to extract information in sEMG signals. Finally, we discuss the future outlook in this field, highlighting the key gaps in current methods to enable seamless natural interactions between humans and machines.

A novel system for providing explicit demand response from domestic natural gas boilers

This paper presents a novel, fully automated system for the implementation of explicit gas Demand Response in the Gas Balancing Market, with real-time control instructions provided to domestic gas boilers. The Demand Response is applied in both the upward and downward direction, enabling the respective gas consumer to provide both upward and downward Balancing Services to the Gas Transmission System Operator. The system targets at the welfare maximization of domestic gas consumers, i.e., the revenues attained by providing Balancing Services to the Gas Transmission System Operator minus the cost of gas supply, while maintaining the house’s indoor temperature within the residents’ comfort limits. Real-time data are derived from interconnected commercial thermostats and used by two Recurrent Neural Networks for each house, in order to attain forecasts for the indoor temperature change and the expected boiler’s modulation levels for the next future time intervals. Such forecasted condition changes within each house are then considered in an optimization model that results in the optimal instruction signal that must be provided to the boiler. The signal concerns the boiler operation level for the following 5 min duration. A Genetic Algorithm is employed for the optimization problem solution. The whole system is deployed using a containerized software architecture to ensure scalability and full-service availability. The implemented real-world tests exhibit that domestic consumers can increase their profits from both gas consumption minimization and from the provision of gas DR services in real-time.

Evaluating Autostereoscopy (AlioscopyTM) Use for Anatomy Education

IntroductionTraditional anatomy learning relies on models and cadaveric specimens that are time and resource intensive to produce, which compromises their accessibility. To mitigate this, the use of three‐dimensional visualization technology (3DVT) to learn anatomy has substantially increased. Still, learning in an immersive virtual reality (VR) environment may pose new challenges, including increased self‐reported levels of cognitive load and cybersickness likely due to its immersive nature that isolates the learner from their surroundings. Autostereoscopy is a novel and potential solution, as it provides a headset‐free stereoscopic view of a three‐dimensional (3D) model. There is, however, a paucity of information about the use and educational efficacy of autostereoscopic 3DVT. The purpose of this study is to examine the strengths and limitations of implementing a non‐immersive autostereoscopic (AlioscopyTM) screen for learning anatomy.MethodsA large‐scale study on the efficacy of VR, autostereoscopy, and 3D printed physical models for learning anatomy is currently underway. We suspect that cognitive load and cybersickness may compete with learning capacity. Based on the literature, we hypothesize the AlioscopyTM screen to represent a sort of middle‐of‐the‐road option, with moderate cognitive load and cybersickness levels (VR&gt;AlioscopyTM&gt;physical), that supports large‐group learning (as opposed to single‐user immersive VR) yet retains the accessibility associated with digital assets (as compared to physical specimens). As such, it is prudent to consider the feasibility of implementing an AlioscopyTM screen for anatomical teaching and summarize the strengths and limitations of the technology.ResultsAccording to the company’s website, 3D images on the 42” AlioscopyTM display we are using can be viewed from 2.5m to 9.0m away, with optimal results at 4.0m, by a theoretical maximum of “20 to 50 people spread over an area of 90°”. We suspect a practical limit of 14 people per display (2 people for each of the 7 viewing zones) and a comfortable limit of 7 (1 per zone). This allows viewers to comfortably situate themselves in a “sweet spot” where each of their eyes receives a clear, distinct image, which is required for the stereoscopic effect. The stereo‐3D effect is prominent, with objects allowed to both protrude from and recess into the display considerably. Display content was created using a plugin (provided by AlioscopyTM) for the videogame engine Unity, allowing existing Unity content to function on the modality easily.ConclusionThe AlioscopyTMscreen represents a novel approach to promoting material accessibility and viewing 3D stereoscopic images in a group setting. The nature of this set up may both decrease the inherent issues most immersive 3DVT impose and offer an opportunity for collaborative learning not available with the use of single‐user headsets.

Comfort limit for asymmetric thermal radiation from a cold wall in neutral to cool environments

Asymmetric thermal radiation from a cold surface, could easily cause local thermal discomfort and even health problems, such as knee osteoarthritis. An experiment with subjects was conducted to study the radiant asymmetry caused by a cold wall at a room temperature of 18 °C, which is the lower limit of the room temperature for heating design in Chinese Building Regulations. The temperature of a single wall was set at 15 °C and 12 °C respectively to simulate a cold exterior wall or window. A control experiment was also conducted under uniform chamber conditions. Groups of 24 healthy college students participated in the experiments. During the first 30 min of the 90-min experiment, the participants could adjust their clothing to approach thermal comfort. The skin temperatures and thermal perceptions of the subjects were measured. The results indicated that clo-value for participants increased with the decrease of the temperature of the cold wall. The skin temperatures and thermal sensations of the limbs were significantly lower than these of the upper torso. The skin temperature of the calf was the lowest. The prolonged exposure to the cold wall decreased the acceptability of the subjects. Accepting 5% of the subjects expressed local discomfort, the acceptable radiant temperature asymmetry was 4.2 K. The limit value obtained in this experiment was significantly lower than the limit value recommended in the existing standards. The lower acceptable value of radiant temperature asymmetry from this study can provide a relevant input to a revision of existing thermal comfort standards.

Improving aerodynamic performance of tall buildings using façade openings at service floors

Modern tall buildings demand innovative solutions for combatting excessive wind-induced vibrations and achieving occupant comfort criteria. The integration of building openings can help reduce wind-induced vibrations, but traditional implementation of this strategy places considerable constraints on architectural and structural design. This paper proposes the treatment of building openings as a minor modification where façade elements at service floors are removed while the underlying structure remains unchanged. A systematic investigation of 18 façade opening configurations is performed to assess the impact opening location and quantity on peak floor accelerations at wind speeds corresponding to comfort and structural design thresholds. A single wind azimuth perpendicular to the building surface is considered. Results indicate that both location and quantity of façade openings affect performance, with a larger number of openings achieving better performance. A single opening was most effective when located at 70% of building height, and compliance with ISO10137 comfort limits was achieved with three or more openings. Results were sensitive to geometric details at service floors, particularly at resonant wind speeds. The study provides valuable insight into the strategic placement of façade openings at services floors to reduce wind response in tall buildings while minimising impact on architectural and commercial considerations.

Customer comfort limit utilisation: Management tool informing credit limit-setting strategy decisions to improve profitability

The key criteria for making business decisions is profit, so when making credit limit-setting strategy decisions, profitability will be the most important driver. The profitability of a credit limit-setting strategy is dependent on the customer’s utilisation of the limits set by the strategy. This points towards a need to determine the extent to which a limit can be increased before a customer’s utilisation will decline beyond the point of being profitable. This paper sets out to define a Customer Comfort Limit Utilisation (CCLU) measure that can be used to gauge a customer’s level of comfort (in terms of limit utilisation) with a newly proposed limit. The CCLU is defined as a function of the customer’s limit utilisation and credit limit; in simpler terms, it can be viewed as a function of balance growth vs limit growth. The neural network model that predicted utilisation first and then the CCLU based on the resulting utilisation values was selected as the final model. Once the final model was determined, it was then verified whether profitability could be improved by using a CCLU measure as a management tool when making limit-setting strategy decisions. It was found that strategies involving CCLU values could lead to increased profitability since CCLU values near 100 (i.e. the customer is 100% comfortable with the new limit and will utilise to the same extent as the previous one) are associated with higher key performance metrics levels.