• Journal of the Institute of Electronics Engineers of Korea CI
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• v.45 no.2
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• pp.1-9
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• 2008

As the security requirements of mobile phones have been increasing, there have been extensive researches using one biometric feature (e.g., an iris, a fingerprint, or a face image) for authentication. Due to the limitation of uni-modal biometrics, we propose a method that combines face and iris images in order to improve accuracy in mobile environments. This paper presents four advantages and contributions over previous research. First, in order to capture both face and iris image at fast speed and simultaneously, we use a built-in conventional mega pixel camera in mobile phone, which is revised to capture the NIR (Near-InfraRed) face and iris image. Second, in order to increase the authentication accuracy of face and iris, we propose a score level fusion method based on SVM (Support Vector Machine). Third, to reduce the classification complexities of SVM and intra-variation of face and iris data, we normalize the input face and iris data, respectively. For face, a NIR illuminator and NIR passing filter on camera are used to reduce the illumination variance caused by environmental visible lighting and the consequent saturated region in face by the NIR illuminator is normalized by low processing logarithmic algorithm considering mobile phone. For iris, image transform into polar coordinate and iris code shifting are used for obtaining robust identification accuracy irrespective of image capturing condition. Fourth, to increase the processing speed on mobile phone, we use integer based face and iris authentication algorithms. Experimental results were tested with face and iris images by mega-pixel camera of mobile phone. It showed that the authentication accuracy using SVM was better than those of uni-modal (face or iris), SUM, MAX, NIN and weighted SUM rules.

• Journal of Broadcast Engineering
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• v.18 no.3
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• pp.481-490
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• 2013

In this paper, an investigation of weapon tracking performance is shown in regard to improving individual weapon performance of aiming objects. On the battlefield, a battle can last only a few hours, sometimes it can last several days until finished. In these long-lasting combats, a wide variety of factors will gradually lower the visual ability of soldiers. The experiments were focusing on enhancing the degraded aiming performance by applying visual tracking technology to roof mounted sights so as to track the movement of troops automatically. In order to select the optimal algorithm among the latest visual tracking techniques, performance of each algorithm was evaluated using the real combat images with characteristics of overlapping problems, camera's mobility, size changes, low contrast images, and illumination changes. The results show that VTD (Visual Tracking Decomposition)[2], IVT (Incremental learning for robust Visual Tracking)[7], and MIL (Multiple Instance Learning)[1] perform the best at accuracy, response speed, and total performance, respectively. The evaluation suggests that the roof mounted sights equipped with visual tracking technology are likely to improve the reduced aiming ability of forces.

• Journal of Korean Public Health Nursing
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• v.7 no.1
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• pp.81-97
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• 1993

This study was carried out to analyze the factors of the perieved symptoms of fatigue of the industrial workers, to examine the inter-relatisnship of the above factors with their general charactenstics and the environments of working area for the examination of their health status and the effective health management of them. This study was undertaken from December 1 to December 20, 1990. The subjets were 495 workers who had worked at the Industrial complex located in Chonbuk Province. The result of this study were as follows: 1. The worker's percieved symptoms of fatigue were classified to the following seven factors; A) Musculo-Skeletal Symptoms, B) Neuro-Psychial Symptoms, C) Optical Symptoms, D) Heart Symptoms, E) Head Symptoms, F) Respiratory Symptoms, G) Genital Symptoms 2. Analysis of the inter-relationship of their percieved symptoms of fatigue with general characteristics; 1) The difference of distribution to their percieved symptoms of fatigue according to sexuality was significant; Female were higher than Male $(p{\leqq}0.001$, p<0.005) 2) The difference of distribution to their percieved symptoms of fatigue according to age was significant; Age group under 24 years of age were higher than the other's group (p<0.001). 3) The difference of distribution to their percieved symptoms of fatigue according to the level of education was significant; Workers who stand on a low intellectual were higher than workers on a high intellectual level. 4) The difference of distribution to their percieved symptoms of fatigue for a week was the highest when worked at sunday. 5) The difference of distribution to their percieved symptoms of fatigue for seasons was high at spring. 3. Analysis of the inter-relationship of their percieved symptoms of fatigue with the environments of working area. 1) The difference of distribution of their percieved symptoms of fatigue according to the working department was significant; Production workers were higher than office workers. 2) The difference of distribution of their percieved symptoms of fatigue related with working posture was significant; Sitting: Musculo-Skeletal symptoms (p<0.05), Optical symptoms (p<0.005) 3) The more dissatisfied with their's own duty they were, the higher became the distribution of their percieved symptoms of fatigue (p<0.001. p<0.005, p<0.05) 4) The more dissatisfied with their working condition they were, the higher became the degree of their percieved symptoms of fatigue (p<0.001. P<0.05) 5) The difference of distribution of their percieved symptoms of fatigue according to kinds of job was significant: Workers who has handled heavy materials were higher than who had not handled $(p{\leqq}0.001$, p<0.05). Workers who has handled chemical materials: Optical, symptoms $(p{\leqq}0.001)$. Workers who has handled dusty materials: Respiratory symptoms (p<0.01) 6) The environment of working area was significantly affected to the distribution of their percieved symptoms of fatigue: Workers complains of a illumination problem; Optical symptoms (p<0.005), Heart symptoms (p<0.005) Workers complains of a ventilation problem: Heart symptoms (p<0.05), Optical symptoms, Heart symptoms (p<0.01) Musculo-skeletal symptoms ($p{\leqq}0.001$)

• Journal of Astronomy and Space Sciences
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• v.33 no.2
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• pp.127-135
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• 2016

Inactive space objects are usually rotating and tumbling as a result of internal or external forces. KOREASAT 1 has been inactive since 2005, and its drift trajectory has been monitored with the optical wide-field patrol network (OWL-Net). However, a quantitative analysis of KOREASAT 1 in regard to the attitude evolution has never been performed. Here, two optical tracking systems were used to acquire raw measurements to analyze the rotation period of two inactive satellites. During the optical campaign in 2013, KOREASAT 1 was observed by a 0.6 m class optical telescope operated by the Korea Astronomy and Space Science Institute (KASI). The rotation period of KOREASAT 1 was analyzed with the light curves from the photometry results. The rotation periods of the low Earth orbit (LEO) satellite ASTRO-H after break-up were detected by OWL-Net on April 7, 2016. We analyzed the magnitude variation of each satellite by differential photometry and made comparisons with the star catalog. The illumination effect caused by the phase angle between the Sun and the target satellite was corrected with the system tool kit (STK) and two line element (TLE) technique. Finally, we determined the rotation period of two inactive satellites on LEO and geostationary Earth orbit (GEO) with light curves from the photometry. The main rotation periods were determined to be 5.2 sec for ASTRO-H and 74 sec for KOREASAT 1.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.202-207
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• 2008

Measures for coping with energy shortage are being sought all over the world. Following such a phenomenon, effort to use less energy in the design of buildings and equipment are being conducted. In particular, a program to evaluate the performance of a building comes into the spotlight. However. indispensable standard wether data to estimate the exact energy consumption of a building is currently unprepared. Thus, after appling standard weather data for four weather factors which were used in previous researches to Visual DOE 4.0, we compared it with the result of the existing data and evaluated them. For the monthly cooling and heating load of our target building, we used revised data for June, July, August, and September during which cooling load is applied. When not the existing data but the revised data was used, the research shows that an average of 14.9% increased in June, August, and September except for July. Also, in a case of heating load, the result by the revised data shows a reduction of an average of 11.9% from October to April during which heating load is applied. In particular, the heating loads of all months for which the revised data was used were more low than those of the existing data. In the maximum cooling and heating load according to load factors, the loads by residents and illumination for which the revised data was used were the same as those of the existing data, but the maximum cooling loads used by the two data have a difference in structures such as walls and roofs. Through the above results, the research cannot clearly grasp which weather data influences the cooling and heating load of a building. However, in the maximum loads by the change of weather data in four factors (dry-bulb temperature, web-bulb temperature, cloud amount, and wind speed) among 14 weather factors, the research shows that 5.95% in cooling load and 27.56% in heating load increased, and these results cannot be ignored. In order to make weather data for Performing energy performance evaluation for future buildings, the flow of weather data for the Present and past should be obviously grasped.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.421-421
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• 2006

The light and energy-efficiency of classical liquid crystal displays is notoriously poor due to the use of absorption-based linear polarisers and colour filters. For instance, the light efficiency of PVAL polarisers is typically between 40 and 45 % and the colour filters have a typical efficiency below 35 % which results in a total light and energy-efficiency of the display below 10 %. In the past, a variety of polarizers were developed with an enhanced efficiency in generating linearly polarized light. Typically, these polarizers are based on the polarisationselective reflection, scattering or refraction of light i.e. one polarisation direction of light is directly transmitted to the LCD/viewer and the other polarization direction of light is depolarised and recycled which results in a typical efficiency for generating linearly polarized light of 70-85 %. Also, special colour filters have been proposed based on chiral-nematic reactive mesogens which increase the efficiency of generating colour. Despite the enormous progress in this field, a need persists for improved methods for generating polarized light and colour based on low cost optical components with a high efficiency. Here, the use of holographic phase gratings is reported for the generation of polarized light and colour. The phase grating are recorded in a photopolymer which is coated onto a backor frontlight for LCDs. Typically the recording is performed in the transmisson mode or in the waveguiding mode and slanted phase gratings are generated with their refractive index modulation at an angle between 20o and 45o with the normal of the substrate. It is shown that phase gratings with a high refractive index modulation and a high efficiency can be generated by a proper selection of the photopolymer and illumination conditions. These phase gratings coupleout linearly polarized light with a high contrast (> 100) and the light is directed directly to the LCD/viewer without the need for redirection foils. Dependent on the type of phase grating, the different colours are coupled-out at a slightly different angle which potentially increases the efficiency of classical colour filters. Moreover, the phase gratings are completely transparent in direct view which opens the possibility to use them in frontlights for LCDs. Holographic polarization gratings posses a periodic pattern in the polarization state of light (and not in the intensity of light). A periodic pattern in the polarization direction of linearly polarized light is obtained upon interference of two circularly polarized laser beams. In the second part of the lecture, it is shown that these periodic polarization patterns can be recorded in a linear photo-polymerizable polymer (LPP) and that such an alignment layer induces a period rotation in the director of (reactive and non-reactive) liquid crystals. By a proper design, optical components can be produced with only first order diffraction and with a very high efficiency (>0.98). It is shown that these diffraction gratings are potentially useful in projection displays with a high brightness and energy efficiency

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.417-423
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• 2011

A series of new quinoxaline-based thiophene copolymers (PQx2T, PQx4T, and PQx6T) was synthesized via Yamamoto and Stille coupling reactions. The $M_ws$ of PQx2T, PQx4T, and PQx6T were found to be 20,000, 12,000, and 29,000, with polydispersity indices of 2.0, 1.2, and 1.1, respectively. The UV-visible absorption spectra of the polymers showed two distinct absorption peaks in the ranges 350 - 460 nm and 560 - 600 nm, which arose from the ${\pi}-{\pi}^*$ transition of oligothiophene units and intramolecular charge transfer (ICT) between a quinoxaline acceptor and thiophene donor. The HOMO levels of the polymer ranged from -5.37 to -5.17 eV and the LUMO levels ranged from -3.67 to -3.45 eV. The electrochemical bandgaps of PQx2T, PQx4T, and PQx6T were 1.70, 1.71, and 1.72 eV, respectively, thus yielding low bandgap behavior. PQx2T, PQx4T, and PQx6T had open circuit voltages of 0.58, 0.42, and 0.47 V, and short circuit current densities of 2.9, 5.29 and 9.05 mA/$cm^2$, respectively, when $PC_{71}BM$ was used as an acceptor. For the solar cells with PQx2T-PQx6T:$PC_{71}BM$ (1:3) blends, an increase in performance was observed in going from PQx2T to PQx6T. The power conversion efficiencies of PQx2T, PQx4T, and PQx6T devices were found to be 0.69%, 0.73%, and 1.80% under AM 1.5 G (100 mW/$cm^2$) illumination.

• Science of Emotion and Sensibility
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• v.13 no.1
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• pp.69-78
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• 2010

LED technology offers versatile lighting control while having a very low environmental impact. Consequently, increasing attention is being paid to the emotional impact of LED lighting. This study investigated whether the chromacity of LED lighting influences people's time perception. To this end, two empirical studies were conducted: First, in experiment I(N=28), the subjects compared their perception of the time duration, which was varied from 3s to 20s, for 6 chromatically nuanced lighting conditions, respectively, with that under a daylight condition. The results showed that, in warm-color nuanced lighting conditions, the subjects perceived time to pass more slowly than in the daylight condition. On the contrary, in cool-color nuanced lighting conditions, the subjects perceived time to pass more rapidly than in the daylight condition. Then, in experiment II(N=39), the subjects were asked to count for 90 seconds while simultaneously performing some cognitive tasks. Confirming the results found in experiment I, the subjects perceived time to pass more rapidly in cool-color nuanced lighting conditions than in warm-color nuanced lighting conditions, although the difference was not statistically significant(p>0.05). In addition, the subjects tended to perceive the time to be shorter when the nuanced color of the light was closer to their preferred color.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.7 no.2
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• pp.52-62
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• 1974

The fresh water prawn, Macrobrachium rosenbergi (De Maan) is a very common species in Info-pacific region inhabiting both fresh and brackish waters in low land areas, and especially abundant in the lower reaches of most rivers which are influenced by seawater, It is one of the largest and commercial species of genus Macrobrachium. As a place of the researches to clear the possibilities of transplantation and propagation of this species in the Far East region the larval development, growth, optimum temperature and metamorphose rate up to first post larvae in aquaruim are cleared under the conditions of salinity $6.58-7.05\%_{\circ}$ Cl, pH 8.0-8.2, the rate of flow 0.3 liter per minute and illumination 3000 lux. Temperature ranged from 27.5 to $28.7^{\circ}C$ during the period of earlier larval development. For the study oil the relationship between temperature and metamorphose rate from zoea to first post larvae, the temperatures in experimental tank were $22.2^{\circ}C\pm1$, $26.1^{\circ}C\pm0.85$, $28.1^{\circ}C\pm0.34$, $30.4^{\circ}C\pm0.66$, $33.7^{\circ}C\pm0.66$, $33.7^{\circ}C\pm0.38$ and $36.8^{\circ}C\pm0.26$. During the work, food used for the larvae was Artemia salina nauplius in the filter-circulation aquariums. This species metamorphosed to the first post-larvae through eleven zoea stages, and the characters of each larval stage are described and optimum temperature for metamorphosis rate and survivals to the first post larvae is $28.1^{\circ}C\pm0.34$.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.9-13
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• 2002

It is well known that the maximum amplitude of accommodation decreases with increasing age.(Presbyopia). With single vision lenses presbyopia can be corrected only for one viewing distance. With progressive power lenses presbyopia can be corrected for all viewing distances. But there are some other changes in the visual system with age which can not be corrected by spectacle lenses. Pupillary diameter decreases and the light transmission of the ocular media decreases. Therefore old people need more light, they need better illumination. Cone density in the retina decreases, this is only one example for changes in the sensory system. These changes in the visual system cause changes in visual functions. At the age of 80 visual acuity has decreased to half. Contrast sensitivity for gratings decreases mainly for high spatial frequencies very important is the increase of stray light in the ocular media and therefore the increase of glare. Veiling luminance increases by a multiple of approximately 4, Dark adaptation gets slower and light sensitivity is approximately 2 log units (factor 100) less when the eye is completely dark adapted. Also colour vision gets worse, especially at low luminances. Elderly people have problems with visual tasks which require divided attention between foveal and peripheral vision. An example is the measurement of the useful field of view. This useful field of view be expanded (improved) by visual training.