Abstract: Recent rapid progress in ICT (Information and Communication Technology) has advanced the penetration of sensor networks (SNs) and their attractive applications. Agriculture is one of the fields well able to benefit from ICT. Plant factories control several parameters related to plant growth in closed areas such as air temperature, humidity, water, culture medium concentration, and artificial lighting by using computers and AI (Artificial Intelligence) is being researched in order to obtain stable and safe production of vegetables and medicinal plants all year anywhere, and attain self-sufficiency in food. By providing isolation from the natural environment, a plant factory can achieve higher productivity and safe products. However, the biggest issue with plant factories is the return on investment. Profits are tenuous because of the large initial investments and running costs, i.e. electric power, incurred. At present, LED (Light Emitting Diode) lights are being adopted because they are more energy-efficient and encourage photosynthesis better than the fluorescent lamps used in the past. However, further cost reduction is essential. This paper introduces experiments that reveal which color of LED lighting best enhances the growth of cultured radish sprouts. Radish sprouts were cultivated in the experimental environment formed by a hydroponics kit with three cultivation shelves (28 samples per shelf) each with an artificial lighting rack. Seven LED arrays of different color (white, blue, yellow green, green, yellow, orange, and red) were compared with a fluorescent lamp as the control. Lighting duration was set to 12 hours a day. Normal water with no fertilizer was circulated. Seven days after germination, the length, weight and area of leaf of each sample were measured. Electrical power consumption for all lighting arrangements was also measured. Results and discussions: As to average sample length, no clear difference was observed in terms of color. As regards weight, orange LED was less effective and the difference was significant (p < 0.05). As to leaf area, blue, yellow and orange LEDs were significantly less effective. However, all LEDs offered higher productivity per W consumed than the fluorescent lamp. Of the LEDs, the blue LED array attained the best results in terms of length, weight and area of leaf per W consumed. Conclusion and future works: An experiment on radish sprout cultivation under 7 different color LED arrays showed no clear difference in terms of sample size. However, if electrical power consumption is considered, LEDs offered about twice the growth rate of the fluorescent lamp. Among them, blue LEDs showed the best performance. Further cost reduction e.g. low power lighting remains a big issue for actual system deployment. An automatic plant monitoring system with sensors is another study target.
Abstract: Lighting systems in interior architecture need to be designed according to the function of the space, the type of task within the space, user comfort and needs. Desired and comfortable lighting levels increase task efficiency. When natural lighting is inadequate in a space, artificial lighting is additionally used to support the level of light. With the technological developments, the characteristics of light are being researched comprehensively and several business segments have focused on its qualitative and quantitative characteristics. These studies have increased awareness and usage of artificial lighting systems and researchers have investigated the effects of lighting on physical and psychological aspects of human in various ways. The aim of this study is to research the effects of illuminance levels of LED lighting on user visual comfort. Eighty participants from the Department of Interior Architecture of Çankaya University participated in three lighting scenarios consisting of 200 lux, 500 lux and 800 lux that are created with LED lighting. Each lighting scenario is evaluated according to six visual comfort criteria in which a reading task is performed. The results of the study indicated that LED lighting with three different illuminance levels affect visual comfort in different ways. The results are limited to the participants and questions that are attended and used in this study.
Abstract: The objective of the study is to assess the
implementation of LED lighting into forest machine work in the dark.
In addition, the paper includes a wide variety of important and
relevant safety and health parameters. In modern, computerized work
in the cab of forest machines, artificial illumination is a demanding
task when performing duties, such as the visual inspections of wood
and computer calculations. We interviewed entrepreneurs and
gathered the following as the most pertinent themes: (1) safety, (2)
practical problems, and (3) work with LED lighting. The most
important comments were in regards to the practical problems of
LED lighting. We found indications of technical problems in
implementing LED lighting, like snow and dirt on the surfaces of
lamps that dim the emission of light. Moreover, service work in the
dark forest is dangerous and increases the risks of on-site accidents.
We also concluded that the amount of blue light to the eyes should be
assessed, especially, when the drivers are working in a semi-dark cab.
Abstract: Although lighting systems powered by Photovoltaic
(PV) cells have existed for many years, they are not widely used,
especially in lighting for buildings, due to their high initial cost and
low conversion efficiency. One of the technical challenges facing PV
powered lighting systems has been how to use dc power generated by
the PV module to energize common light sources that are designed to
operate efficiently under ac power. Usually, the efficiency of the dc
light sources is very poor compared to ac light sources. Rapid
developments in LED lighting systems have made this technology a
potential candidate for PV powered lighting systems. This study
analyzed the efficiency of each component of PV powered lighting
systems to identify optimum system configurations for different
applications.
Abstract: Although White LED lighting systems powered by solar cells have presented for many years, they are not widely used in today application because of their cost and low energy conversion efficiency. The proposed system use the dc power generated by fixed solar cells module to energize White LED light sources that are operated by directly connected White LED with current limitation resistors, resulting in much more power consumption. This paper presents the use of white LED as a general lighting application powered by tracking solar cells module and using pulse to apply the electrical power to the White LED. These systems resulted in high efficiency power conversion, low power consumption, and long light of the white LED.
Abstract: Light is one of the most important qualitative and
symbolic factors and has a special position in architecture and urban
development in regard to practical function. The main function of
light, either natural or artificial, is lighting up the environment and
the constructional forms which is called lighting. However, light is
used to redefine the urban spaces by architectural genius with regard
to three aesthetic, conceptual and symbolic factors. In architecture
and urban development, light has a function beyond lighting up the
environment, and the designers consider it as one of the basic
components. The present research aims at studying the function of
light and color in architectural view and their effects in buildings.
Abstract: We present a white LED-based optical wireless
communication systems for indoor ubiquitous sensor networks. Each
sensor node could access to the server through the PLC (Power Line
Communication)-Ethernet interface. The proposed system offers a
full-duplex wireless link by using different wavelengths to reduce the
inter-symbol interference between uplink and downlink. Through the
1-to-n optical wireless sensor network and PLC modem, the mobile
terminals send a temperature data to server. The data transmission
speed and distance are 115.2kbps and about 60cm, respectively.