Different Levels Of Illumination Research Articles

INTENSITAS CAHAYA ALAMI PADA RUANG KELAS PERKULIAHAN


 
 
 Title: Natural Light Intensity Analysis in Classroom; Case Study: Classroom at Bosowa University
 Lighting is an important part of buildings in supporting the productivity of human labor. Insufficient lighting can interfere with human activities and could cause health problems, like eye disorders. Building design must consider the functions and needs so that residents can feel comfortable. Good lighting levels can be achieved by utilizing natural and artificial lighting. The purpose of this study was to analyze the level of illumination in a room that is directly related to the openings of the building envelope and to analyze the different levels of illumination in classrooms with different orientations. Quantitative research methods by distributing measurement data in the form of tables, diagrams and graphs. Data analysis was performed using statistics and data analysis techniques, the results of the measurement were statistically descriptive. This study analyzed the differences in the level of illumination in the northern orientation and southern orientation classrooms. Based on the results of the analysis it can be concluded that the orientation of the building affects the level of illumination in the room. During the day the level of illumination is higher in the direction of orientation north than the direction of orientation south, especially the measurement point in the area close to the openings of the building envelope, but in this study the direction of classroom orientation towards the south is higher the level of illumination compared to the north orientation classrooms. This is understood by the treatment of building glass sheaths in the north orientation direction in the form of the use of frosted glass wallpaper, so it can be concluded that changes to the building facade affect the level of room illumination. The results of this study are expected to be a reference in building facade concepts and designing energy-efficient buildings.
 
 

Effects of illuminance and contrast on the reading of Chinese text by myopes

Twenty-four young adults with myopia in both eyes and no anisometropia participated in this study. Observers were instructed to read one A4-sized page of Chinese text at different levels of illuminance and text contrast, while their reading distance, head tilt angle and reading speed were recorded using an electromagnetic motion tracking system. Four illuminances (3, 30, 300 and 600 lx) and two text contrast levels (90% and 45%) were tested in randomised order. Observers tended to shorten their reading distance and increase their head tilt angle when reading at low illuminance. In addition, their reading speed was markedly slower at low illuminance and low contrast. These effects were found for both text contrast conditions but were greater at low contrast. Illuminance and text contrast play a critical role in myope’s reading behaviour. An illuminance of 300 lx or more with high-contrast text allows for good reading posture and rapid reading of Chinese text.

Comparison between psychological responses to ‘object colour produced by paint colour’ and ‘object colour produced by light source’

This study aimed to systematically analyse the differences in emotions evoked by the same colour, depending on whether it is an object or light colour. To this end, an assessment was conducted using mock experimental spaces created with either object or light colours (red, green, blue and yellow) and with different levels of illuminance (10 lx or 100 lx). The participants comprised 30 graduate students (19 men; 20–30 years) majoring in colour and lighting, and the vocabulary selected for emotional assessment included the words ‘comfortable’, ‘stable’, ‘tense’, ‘anxious’, ‘cool’ and ‘warm’. The results demonstrated differences between participants’ emotional reactions to the object colour and light colour environments when the same colour was used. For red, green and blue, the object colour was rated higher than the light colour for positive responses of ‘comfortable’ and ‘stable’. For yellow, however, the response differed only slightly between object colour and light colour. Finally, emotional differences varied significantly depending on illuminance level for object colour but not for light colour.

БИОТОПИЧЕСКИЕ ОСОБЕННОСТИ РАСПРОСТРАНЕНИЯ И УСТОЙЧИВОСТЬ К АНТРОПОГЕННОМУ ВОЗДЕЙСТВИЮ LISTERA OVATA (L.) R.BR. В КИРОВСКОЙ ОБЛАСТИ

Stash ovate (Listera ovata (L.) R. Br.) – herbaceous short-rooted perennial. The purpose of the study is to identify the environmental preferences of Listera ovata and its resistance to anthropogenic impact on the territory of the Kirov region. As a result of phytoindication of the studied Listera ovata habitats, ecological characteristics were obtained using six H. Ellenberg scales (1974). According to the illumination scale, which evaluates the ratio of plants to the relative illumination prevailing in the habitat of the species, Listera ovata grows at different levels of illumination: as in open habitats with 60–80 % illumination. In relation to the thermoclimatic factor that evaluates heat / cold resistance, the studied species is an inhabitant of a temperate climate (the 5th stage of the Ellenberg scale). On the continental scale Listera ovata is characterized as a suboceanic species (4th stage of the Ellenberg scale), which corresponds to the geographical distribution zone of the species within the Kirov region. In relation to soil moisture, the distribution of the species in habitats with soils ranging from medium-wet (5th stage of the Ellenberg scale) to wet (6th stage of the Ellenberg scale) was noted. On the scale of soil acidity, which determines the dependence of species on acid-base soil conditions, Listera ovata occupies habitats characterized from moderately acidic (5th stage of the Ellenberg scale) to weakly alkaline soils (7th stage of the Ellenberg scale). According to the nitrogen richness scale, which shows the total supply of nutrients (N, K, P, Mg) in the soil, the species is confined to habitats with moderately provided basic nutrients (5th stage of the Ellenberg scale). Analysis of hemerobicity by species composition in plant communities showed that the studied plant communities with Listera ovata are mainly represented by oligo and meso-hemerobic species: from 30.56 to 37.78 %. These are species of communities that are close to natural, that tolerate irregular weak influences, and species of semi-natural communities that are resistant to extensive influences (Vaccinium vitis-idaea, Fragaria vesca, Asarum europaeum, Pimpinella saxifraga, Melica nutans, Maianthemum bifolium, Vaccinium myrtillus). The share of species of natural communities that do not tolerate anthropogenic influence is 1.65 %. About 21 % are occupied by species far from natural communities that are resistant to intensive use (Melilotus albus, Pastinaca silvestris, Calamagrostis epigeios). Weed species of natural and anthropogenic communities that suffer regular severe disturbances account for 7.67 % (Trifolium repens, Galium odorata, Taraxacum officinale). The share of specialized weed species of intensive crops is 4.06 % (Chamaenerion angustifolium, Tussilago farfara, Cirsium arvense, Galium aparine, Anthriscus sylvestris). Types of completely disturbed ecosystems in the studied habitats were not identified. All studied phytocenoses with L. ovata are dominated by anthropophobic species: from 62 to 77 %. The percentage of anthropotolerant species is not high and varies from 23 to 38 %.

Применение ближней инфракрасной спектроскопии для анализа химического состава базилика

The near infrared spectroscopy method investigated the chemical composition of fragrance basil plants (Ocimum basilicum) with green leaf colour, the Stella variety, which is a green culture with a short period of vegetation. The lighting was carried out using 400 W arc sodium mirror lamps (DNaZ 400), with a light flux of 46 thousand. Lm, whose spectrum is predominantly orange-red light (650 nm), is most effective for photosynthesis. The level of illumination when growing basil was 10 thousand and 15 thousand lk. The longitude of the day, taking into account the lighting, was 16 hours. In the above-ground portion of the basil plants, the protein, fiber, lipid, ash and starch content was determined by near infrared spectroscopy on an infrared SpectraStar XT analyzer, model 1400ХТ-3, full scanning range 1400-2600 nm. The increase in illumination stimulated photosynthetic activity and the synthesis of assimilates, achieving, at a certain level of illumination, an equilibrium state between the amount of CO2 absorbed and released. Basil plants have been shown to react differently to different levels of illumination. Using BIC spectroscopy, it was found that with increased illumination, the protein content of basil plants decreased from 23.4% at 10,000 lx to 20.1% at 15,000 lx, and the starch content increased from 30.1% at 10,000 lx to 43.7% at 15,000 lx. The content of basil in plants at different levels of illumination of such indicators as fat, ash and fiber remained at the same level and amounted to 3.06, respectively; 8.51 and 26.4% at 10 thousand lx and 2.80; 8.08 and 26.5% at 15 thousand lux.

Regulatory Features of Solar Battery Charger

The aim of the work is the analyze the of regulation characteristics of a switching voltage regulator of the step-up type. The case when the regulator's power source is a solar battery and the load is a rechargeable battery is considered. It is noted that in this mode, the switching voltage regulator operates in the mode of regulation of the output current (battery charging current). The case when the battery voltage is equal to the maximum no-load voltage of the solar battery is analyzed. It is shown that in this case regulation characteristic of the input current of the switching regulator coincide with the output characteristics of the solar battery, in which the axis of voltage is replaced by the axis of the relative open-time of the key of the switching regulator. Taking into account the received input regulation characteristics, the output regulation characteristics of the switching regulation were built. If the battery voltage is less than the maximum no-load voltage of the solar battery, the regulation characteristics of the switching regulation will coincide with a limited section of the output characteristics of the solar battery. In this case, the correspondence between the voltage scale and the scale of the relative open time of the key of the switching regulator will depend on the ratio between the battery voltage and the maximum no-load voltage of the solar battery. The conditions, under which the maximum amount of electrical energy will be obtain from the solar battery at different levels of illumination were analyzed. The condition, under which the inductance of the switching regulator will receive a discontinuous current mode were analyzed. For different levels of illumination of the solar battery, as well as depending on the magnitude of the inductance, the critical value of the relative open-time time of the key of the switching regulator, at which a discontinuous current mode occurs in the inductance were determined. Taking into account the possibility of the occurrence of such a mode, the adjustment of the previously obtained regulation characteristics were carried out. The normalized graphs of the regulation characteristics for the input and output current of the switching regulator, taking into account the possibility of the occurrence of a discontinuous current inductance in it are given. Recommendations on the expediency of using various sections of these characteristics, when charging batteries from a solar battery, are given. The dependence of the amount of under-received electrical energy from the solar battery, which is related to the pulsating nature of the input current of the switching regulator and the selected battery voltage value is analyzed. Recommendations regarding the choice of the battery voltage for a solar cell of the selected type are given.

A Comparative Study of Clustering Validation Indices and Maximum Entropy for Sintonization of Automatic Segmentation Techniques

Automatic image segmentation is a fundamental task in many applications such as video surveillance, image retrieval, medical image analysis, recognition, tracking and objects classification. This task is not easy due to the complexity of image features as well as the number of objects within the images which is unknown in most of the time. However, the correct tuning of the parameters associated with the automatic segmentation algorithms can improve the levels of precision in the object segmentation in the images. This paper proposes the use of clustering validation indices and maximum entropy as cost functions to quantify the quality of segmentation in order to find the optimal parameters of the automatic segmentation techniques. The impact of using clustering validation indices and maximum entropy was evaluated in the automatic segmentation algorithms, K-Means, Watershed and Statistical Region Merging (SRM), using four image databases with images containing different numbers and sizes of objects and different levels of illumination. The results obtained reveal that the use of clustering validation indices and maximum entropy for tuning the automatic segmentation algorithms results in better segmentations with a number of segmented objects close to what really exists in the images, while these results are competitive with the works reported in the literature.

Automated system for determining parameters of a solar cell model

An automated system is developed, which allows measuring the light and dark current-voltage characteristics (CVC) of a solar cell (SC). It consists of a STM32 based control unit, a digital-to-analog converter, a voltage-current transformation circuit, a current and voltage sensor and a laptop with a LabVIEW graphical programming environment. The digital voltage value from STM32 is transmitted to the AD5624R DAC via the SPI interface. AD5624R is a 12 bit DAC with built-in reference voltage 2,5 V. In this configuration, the accuracy of the voltage control is 1,2 mV and the accuracy of the current setting is 40 μA. INA226 sensor was used to measure the voltage on the sample and the current flowing through it. The current is measured as the voltage drop across the shunt resistor, which is connected to the corresponding sensor inputs, using the built-in 16-bit ADC. A shunt resistor with a resistance of 0.1 Ohm is used, which allows measuring the current up to 800 mA with a resolution of 25 μA. The readings of the sensor were calibrated using the precision voltmeter B7-46. Measurement and data processing is carried out with a virtual device created in the LabVIEW environment. As a microcontroller, the SM32F401RE Nucleo development board was used. This unit provides control of the DAC, the current sensor INA226, connection of the circuit for measuring light or dark CVC, as well as recording and storing the data received from sensors in the computer. By measuring the light and dark current-voltage characteristics it is possible to obtain an approximate solar cell model, the parameters of which depend on the illumination and temperature. Solar cell light CVC is used to determine the photocurrent. By its value at a certain temperature and luminosity, it’s possible to define the photocurrent at different temperatures and luminosity levels. The saturation current and the parameter α of the solar cell are calculated using the dark CVC. With the obtained data, a model of a solar cell is defined, which can be further used to determine the maximum power point at different levels of illumination and temperature. With information about the maximum power point, it is possible to calculate the optimal resistance value for the solar cell and to provide the corresponding control signal to the voltage converter. An approach for calculating the parameters of the SC model from its CVC is described and used to determine the MPP (maximum power point) of the solar cell module. The difference with the experimental data was 6.6%. In further research, the study of methods for calculating the parameters of the SC, which could provide a more accurate model, will be continued.

Quantitative Assessment of Factors Affecting Visual Acuity by Changing the Luminance

In today's deregulated, the world continues its voyage towards modernization, and there is a great demand for inventive in product and services development, Visual acuity measurement has become one of the most successful clinical tests of visual function, Visual Acuity (V. A) Commonly refers to the clarity of vision, in another dimension, although V. A. is an estimate of the visual system's ability to resolve the details. However, the estimates of Visual acuity are taken by evaluating and measuring the eye's ability to realize and resolve varying sizes of letters and shapes in Snellen's chart. More recently attention has focused on the luminance of the visual acuity chart while it is essential to consider the overall room illumination during visual acuity measuring. It has commonly been assumed that the rise in ambient room illumination decreases the size of the pupil. A smaller pupil increases the depth of focus furthermore reductions the peripheral light rays that entering into the eye. Thus, the reduced pupil diameter great less spherical deviation and other higher order aberration, such as coma aberration. A clinician may achieve an artificially better estimate of visual acuity in a brightly-lit examination room. The aims of this study is to determine the factors affecting Visual Acuity by changing the luminance. Fourteen patients aged 19 to 24 years were chosen. Monocular visual acuity patients were assessed under five different luminance levels (different colors), and V. A was measured in the patients with each room color. The results showed that there is a clear difference in the measurement of V. A when the light was changed from color to another. The visual acuity of patients was assessed using the five different levels of illumination.

Development of a New High Dynamic Range Technique for Solar Flux Analysis Using Double-CCD Optical Camera

In solar central receiver (SCR) systems, camera-based tracking and control strategies have been widely developed and tested. The camera, usually with a single CCD, captures images of the sun reflected by thousands of heliostats on the central receiver. The captured images are then analysed to allow the evaluation of solar flux. For accurate analysis process, the camera must have a high dynamic range (HDR) to give real and accurate information about the captured scene. In the present article, a new methodology has been developed using a double-CCD optical camera for improvement of dynamic range of the captured solar flux image. An experimental calibration set-up is adopted for accurate estimation of the camera response function. The double-CCD camera is used for acquiring two images at the same instant with two different levels of exposure. The two captured images are then merged into a single HDR image using a new proposed weighting function. The enhanced optical performance of the proposed weighting function has been demonstrated by comparison with the previous HDR image generation weighting functions at different levels of illumination. Investigation of the capability of the proposed methodology for the analysis of beam accuracy and optical quality of SCR systems show that the present proposed method leads to more accurate solar flux analysis because of the improvement in the resolution of details of the final merged image.

Analisis Pengaruh Intensitas Penerangan Pada Laboratorium Dan Bengkel Jurusan Teknik Elektro

Lighting is one of the most important components in planning a building. To do all the activities that exist in the room of a building then needed a sufficient intensity of lighting, so that it can be carried out with maximal especially related to work practices conducted in the laboratory for the purposes of teaching and learning process. Lighting in the room when viewed from the quality is a strong illumination or lighting level is required where for different types of activities will require different levels of illumination. The results of this study is based on the use of light intensity in the laboratory and workshop through a measurement of the intensity of room lighting using SNI 16-7062-2004 standard and calculate the electrical energy it uses. Measurement of landing intensity was measured using lux meter measuring instrument. Measurements are done at 09.00, 12.00 and 15.00. The room is in accordance with the standard of environmental health requirements of office and industrial work with an area of 118.80 m2 has a lighting intensity (E) of 183.82 lux. While the intensity of illumination (E) 20.85 - 85.44 lux is recommended for the addition of the number of points of light

MODERN APPROACHES TO DYSPHOTOPSIA ANALYSIS, ASSESSMENTOF PATIENT SATISFACTION AND SPECTACLE INDEPENDENCE AFTER MULTIFOCALINTRAOCULAR CORRECTION: REVIEW

The core target of multifocal IOLs implantation is to provide advanced visual quality at different distances without spectacle or contact lenses that can be valuable when monofocal IOLs are implanted. Patients with monofocal IOLs need spectacles or contact lenses for the near and intermediate distance's vision. Multifocal intraocular lenses due to the optical part construction provide spectacle independence for patients in the postoperative period. The aim of this review was to analyze the modern approach to the several aspects of multifocal intraocular correction: spectacle independence, dysphotopsia, patient satisfaction. Patients’ questionnaire after surgery provides the data for evaluation of the quality of life, vision satisfaction at all range of distances on different levels of illumination, and patient activities of daily living. During the long period, a photic phenomenon (dysphotopsia) had been discussed in the literature as the principal reason for decrease of patients satisfaction with the treatment and lens explantation. Recently, high grade of spectacle independence and low risk of photic phenomena after modern multifocal IOLs implantation determine high-level patient satisfaction after cataract surgery. Multifocal intraocular correction is the effective technology for restoring passive accommodation that the wide range of the clinical studies proved. This review analyzes 33 studies (32 clinical studies and 1 metaanalisis) published in international peer-reviewed targeted titles.

Kinetics of the Hydrogen Evolution Reaction at Rh-Doped SrTiO3 Driven By Visible Light: A Study By Photoelectrochemical Impedance Spectroscopy

Because of the gradual exhaustion of carbon-based fuels and the problematic issues associated with their combustion, modern human societies are urged to find alternative, sustainable and renewable energy sources.1 The enormous amount of radiative energy arriving to earth from sun appears as an excellent alternative source of primary energy. In this context, the use of semiconducting materials that can absorb visible light and transform solar radiations into clean fuels is a topic of significant scientific interest. In particular, the hydrogen evolution reaction (HER) that produces hydrogen from earth-abundant water is a widely targeted reaction.2 In electrochemistry, the HER is a multistep process for which a large variety of efficient electrocatalysts, operating in different media and at different pH, have already been developed. But the kinetics of water photo-reduction at photocathodes involves different reaction steps and still requires improvement. In this communication, we report on the kinetics of water photo-reduction using Rh:SrTiO3 as light-absorbing semiconductor. The charge transfer (kt ) and recombination (kr ) rate constants have been determined in order to unravel the heterogeneous mechanism for the HER that prevails at Rh:SrTiO3 / electrolyte interfaces. Rh:SrTiO3 samples were prepared by calcinations of appropriate precursors. The X-ray diffraction pattern of the semiconducting powder confirmed the perovskite structure of SrTiO3 as a pure phase. Though, the presence of Rh as the dopant could not be put in evidence by XRD, an indication that the substitution of Rh4+ atoms by Ti4+ in the crystal lattice did not distort appreciably the structure of the solid. Further characterization was performed by X-ray photoelectron spectroscopy (XPS), and the presence of Rh in the sample was clearly established. The band structure of the photoelectrode was characterized by UV-Vis and Diffuse Reflectance spectroscopies, suggesting a band gap of 2.7 eV as reported before.3 Linear sweep voltammetry at different levels of illumination (λ > 450 nm) showed an increase in cathodic currents upon illumination, which expressed the role of the device as a photocathode. Subsequently, the photoelectrode was characterized using photoelectrochemical impedance spectroscopy (PEIS). The shape of PEIS-diagrams was found to change upon potential cycling. This may be due to either the accumulation of reactive intermediates at the surface of the photoelectrode or to the reduction of Rh4+ to Rh3+ in the material that causes the catalytic activity of the material. PEIS-diagrams then attained a stable shape which permitted to perform a full kinetic analysis. It was observed that kt was independent of light intensity and that kr increased slightly with increasing light power. Conversely, kt increased exponentially while the electrode potential became more negative. Such fact indicated the presence of surface states that caused Fermi level pinning. As a result, an important part of the applied potential dropped in the Helmholtz layer. The Tafel plot of ln kt vs. applied potential exhibited a slope of 93 mV/dec (α = 0.28), which suggested that water discharge at the surface (Volmer reaction, H2O + e- + M = M-H + OH-) was the rate determining step. Overall, a thorough kinetic determination of the HER, photo-assisted by visible light, has been performed and details will be reported during the Meeting.

Effects of Tai Chi Exercise on body stability among the elderly during stair descent under different levels of illumination

ABSTRACTThe elderly are prone to stair descent falls under low illumination. Tai Chi, a traditional Chinese conditioning exercise, has been proved to improve body stability by altering body condition, gait, and proprioception. This study investigates whether Tai Chi exercise could improve body stability during stair descent under high and low illumination. Three groups of elderly women who practice Tai Chi, brisk walking, and no exercise were included. They descended from a simulated staircase. Tai Chi participants decreased horizontal velocity, centre of mass (COM) sway, and increased foot clearance compared with other participants, these movements could increase body stability; Compared with under high illumination, Tai Chi participants decreased horizontal velocity, loading rate, braking impulse, and increased inclination angle, COM sway, centre of pressure displacement under low illumination. Tai Chi participants were more sensitive to the difference in illumination, and took corresponding strategies to stabilize their bodies during stair descent.

Effect of Illumination over Positive Fusional Vergence when Using VDU as Target

Background: To find out the changes in the positive fusional vergence at near, under different room illuminations while using VDU (Visual Display Unit) as a target. Method: A cross sectional study was performed by using convenience sampling method. The study subjects comprised of 33 Malaysians aged between 15 to 35 years regardless of race and gender. This research was done within a period of six months (April 2015 to September 2015) at Twintech vision clinic. The data were analyzed by using a repeated measure Friedman Test to investigate the changes in positive fusional vergence at near under different room illuminations. Result: 33 subject’s data were analyzed, out of which 17 male and 16 female. Positive fusional vergence at near changed significantly in three different levels of room illumination (p=0.012, p=0.003 and p=0.006 for Blur, Break and Recovery respectively). However, positive fusional vergence between gender was not significant (p>0.05). Conclusion: There is a statistically significant difference in positive fusional vergence for near under different level of illuminations. Moreover, under low illumination the positive fusional vergence seems to be higher. There is no significant difference observed between genders for positive fusional vergence at near.

Comparison of Amplitude of Accommodation in Different Room Illumination while Using VDU as a Target

Purpose: To compare the measurement of the amplitude of accommodation (AA) in different room illumination while using visual display unit (VDU) as a target. Method: A non-randomized, cross-sectional study includes 32 Malaysians aged between 15 to 35 years despite races and gender. Convenience sampling method was used. The data were analyzed by using one-way repeated measure ANOVA, to investigate the changes in the amplitude of accommodation in a different level of illuminations (23 Lux, 17 Lux, and 4 Lux). Result: 32 subjects’ data were analyzed. The amplitude of accommodation measured via a minus-lens method. No significant change has been observed among three levels of room illumination (p>0.05) with the mean difference of 0.222DS from the first room illumination to third room illumination. Furthermore, the association of AA among genders, age groups, race and refractive error for different levels of room illumination was not significant (p>0.05). However, an amplitude of accommodation between 15-21years and 22-28 years showed significant (p=0.047) difference in the first level of room illumination. Conclusion: The level of illumination has no clinically significant effect on the amplitude of accommodation. Key Words: Amplitude of Accommodation, room illumination, visual display unit (VDU), minus lens method

Direct determination of defect density of states in organic bulk heterojunction solar cells

The measurement of the occupied trap density of states (DOS) is important for optimization of organic bulk heterojunction solar cells. We demonstrate a direct method for obtaining it from the trap related peak in capacitance-voltage characteristics under different levels of illumination, and its correlation with the dark current density-voltage characteristics. We use the method to measure the parameters of DOS, occupied trap distribution, and its temperature dependence for poly(3-hexathiophene) (P3HT):phenyl-C61-butyric acid methyl ester (PCBM) based solar cells. The total occupied trap concentration is approximately 7 × 1015 cm−3 with a standard deviation for a truncated Gaussian distribution varying between 32 and 44 meV in the temperature range of 310–270 K within a total Gaussian DOS with a standard deviation of 92 meV.

An efficient method for video shot boundary detection and keyframe extraction using SIFT-point distribution histogram

In today’s digital era, there are large volumes of long-duration videos resulting from movies, documentaries, sports and surveillance cameras floating over internet and video databases (YouTube). Since manual processing of these videos are difficult, time-consuming and expensive, an automatic technique of abstracting these long-duration videos are very much desirable. In this backdrop, this paper presents a novel and efficient approach of video shot boundary detection and keyframe extraction, which subsequently leads to a summarized and compact video. The proposed method detects video shot boundaries by extracting the SIFT-point distribution histogram (SIFT-PDH) from the frames as a combination of local and global features. In the subsequent step, using the distance of SIFT-PDH of consecutive frames and an adaptive threshold video shot boundaries are detected. Further, the keyframes representing the salient content of each segmented shot are extracted using entropy-based singular values measure. Thus, the summarized video is then generated by combining the extracted keyframes. The experimental results show that our method can efficiently detect shot boundaries under both abrupt and gradual transitions, and even under different levels of illumination, motion effects and camera operations (zoom in, zoom out and camera rotation). With the proposed method, the computational complexity is comparatively less and video summarization is very compact.

The Effect of Illuminance and Color Temperature of LED Lighting on Occupants' Perception and HRV

Purpose: It is crucially important that indoor luminous conditions of built environments be carefully studied so as to promote comfort and occupants’ well-being. Method: The current study therefore focuses on the lit aspect of an enclosed space considered to be a resting room (4.5 m X 6.32 m X2.5 m). Particularly, on the effect that light levels and light color temperatures have on the physiological and psychological responses of resting occupants. To do so, a questionnaire survey was carried out on 50 subjects. The independent variables for the experiment included 9 different luminous environment conditions setup using 3 different levels of illuminance (50 lx, 150 lx, 300 lx) and 3 different color temperatures (2000 K, 3800 K, 5600 K). A questionnaire was utilized in determining which conditions were preferred by occupants. Result: As it turns out, indoor luminous environment designed for relaxation purposes should display luminance levels of at least 150 lx and 3800 K of color temperature in order to provide a visually comfortable environment suitable for the occupant’s relaxation while at the same time promoting the psychological and HRV well-being of resting occupants. ⓒ 2015 KIEAE Journal.

Postharvest Handling Conditions Affect Internalization of Salmonella in Baby Spinach during Washing

Internalization of foodborne pathogens in fruits and vegetables is an increasing safety concern. The aim of this research was to assess the potential for internalization of an enteric pathogen (Salmonella enterica serotype Typhimurium) in a leafy vegetable (baby spinach) during washing as influenced by three postharvest handling conditions: (i) illumination, (ii) negative temperature differential, and (iii) relative humidity (RH). To compare these potential postharvest handling conditions, leaves were exposed to different levels of illumination (0, 1,000, and 2,000 lx), temperature differential (5, 11, 14, 20, and 26°C), and RH (99, 85, and 74%) for a short time before or during washing. Washing of baby spinach was carried out in water containing green fluorescent protein-tagged Salmonella Typhimurium (6.5 log CFU/ml) at 5°C for 2 min, followed by surface disinfection with chlorine (10,000 μg/ml) for 1 min, two rinses in water for 10 s, and spin drying for 15 s. Internalization was assessed by enumerating the pathogen on Salmonella-Shigella agar and by confocal laser scanning microscopy. Illumination of spinach leaves before and during washing and a negative temperature differential during washing did not significantly (P > 0.05) increase the number of internalized bacteria. However, exposure of leaves to low-RH conditions before washing, which reduced the tissue water content, decreased internalization of Salmonella compared with internalization in baby spinach exposed to high RH (P ≤ 0.05). Green fluorescent protein-tagged Salmonella Typhimurium was visualized by confocal laser scanning microscopy at a depth of up to 30 m m beneath the surface of spinach leaves after exposure to a high inoculum level (8 log CFU/ml) for an extended time (2 h). Results show that internalization of Salmonella into baby spinach leaves can occur but can be minimized under specific postharvest handling conditions such as low RH.