3,150 research outputs found
Hybrid Ventilation System and Soft-Sensors for Maintaining Indoor Air Quality and Thermal Comfort in Buildings
Maintaining both indoor air quality (IAQ) and thermal comfort in buildings along with optimized energy consumption is a challenging problem. This investigation presents a novel design for hybrid ventilation system enabled by predictive control and soft-sensors to achieve both IAQ and thermal comfort by combining predictive control with demand controlled ventilation (DCV). First, we show that the problem of maintaining IAQ, thermal comfort and optimal energy is a multi-objective optimization problem with competing objectives, and a predictive control approach is required to smartly control the system. This leads to many implementation challenges which are addressed by designing a hybrid ventilation scheme supported by predictive control and soft-sensors. The main idea of the hybrid ventilation system is to achieve thermal comfort by varying the ON/OFF times of the air conditioners to maintain the temperature within user-defined bands using a predictive control and IAQ is maintained using Healthbox 3.0, a DCV device. Furthermore, this study also designs soft-sensors by combining the Internet of Things (IoT)-based sensors with deep-learning tools. The hardware realization of the control and IoT prototype is also discussed. The proposed novel hybrid ventilation system and the soft-sensors are demonstrated in a real research laboratory, i.e., Center for Research in Automatic Control Engineering (C-RACE) located at Kalasalingam University, India. Our results show the perceived benefits of hybrid ventilation, predictive control, and soft-sensors
Linkage between knowledge management practices towards library user’s satisfaction at Malaysian University Libraries
Academic library services have begun to apply various knowledge management (KM)
practices in the provision of library services. KM has been developed to enhance the use
of organizational knowledge through practices and organizational learning. KM
practices include the creation, capture and/or acquisition of knowledge, its retention and
organization, its dissemination and re-use, and general responsiveness to the new
knowledge. The focus of this research is the assessment of KM practices, particularly
creation, acquisition, capture, sharing, recording and preservation, and their effects on
Library User’s Satisfaction (LUS) in Malaysian university libraries. The objective of this
research is the development of a model to enhance KM processes (i.e. Creation,
acquisition, capturing, sharing, recording, and preserving) and to improve library users’
satisfaction. A quantitative approach in research methodology is employed (e.g.
Questionnaire) for the purpose of generating new knowledge and understanding of
library concerns. The findings of this research show that the overall KM practice at six
Malaysian university libraries is at a high level. The findings from the structural model
indicated that two KM processes, namely knowledge creation and acquisition, are not
supported in terms of KM practices at Malaysian university libraries. Other KM
processes, namely capturing, sharing, recording, and preserving are fully supported
towards KM practices in the library. Hence, the major contribution of this research is a
model, namely KM Practice-Library User’s Satisfaction (KMP-LUS) highlighting six
KM processes based on strong Structural Equation Modeling (SEM) fit indices
TVOCs and PM 2.5 in Naturally Ventilated Homes: Three Case Studies in a Mild Climate
In southern Europe, the present stock of social housing is ventilated naturally, with practice
varying in the di erent seasons of the year. In winter, windows are kept closed most of the day
with the exception of short periods for ventilation, whereas the rest of the year the windows are
almost permanently open. In cold weather, air changes depend primarily on the air infiltrating
across the envelope and when the temperature is warm, on the air flowing in through open windows.
CO2, PM2.5, and TVOC concentration patterns were gathered over a year’s time in three social
housing developments in southern Europe with di erent airtightness conditions and analyzed to
determine possible relationships between environmental parameters and occupants’ use profiles.
Correlations were found between TVOC and CO2 concentrations, for human activity was identified
as the primary source of indoor contaminants: peak TVOC concentrations were related to specific
household activities such as cooking or leisure. Indoor and outdoor PM2.5 concentrations were
likewise observed to be correlated, although not linearly due to the presence of indoor sources.
Ventilation as presently practiced in winter appears to be insufficient to dilute indoor contaminants in
all three buildings, nor does summertime behavior guarantee air quality
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