• Transactions on Electrical and Electronic Materials
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• v.17 no.1
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• pp.37-40
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• 2016

Performance enhancement of organic light-emitting diodes (OLEDs) is investigated in a device structure of ITO/TPD/Alq₃/LiF/Al and ITO/TPD/Alq₃/BCP/LiF/Al. Here, bathocuproine (BCP) is used as an electron-transport layer. Current density-voltage-luminance characteristics of the OLEDs show that the performance of the device is better with BCP layer than without BCP layer. The current density, luminance, luminous efficiency, and external-quantum efficiency are improved by approximately 22%, 50%, 2%, and 18%, respectively. Since the BCP layer lowers the electron energy barrier, electron transport is facilitated and the movement of hole is blocked as the applied voltage increases. This results in an increased recombination rate of holes and electrons.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.601-604
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• 2002

We propose modified fence electrode structure for manufacturing of ITO-electrode-free PDP. Luminance, luminance efficiency and addressing time for the proposed structure shows performance improvement about 25 percent. Our results can be used for the reduction of manufacturing cost without degradation of PDP performance.

• JSTS:Journal of Semiconductor Technology and Science
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• v.15 no.1
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• pp.60-67
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• 2015

This paper proposes an image-dependent color image enhancement method that uses adaptive luminance enhancement and color emphasis. It effectively enhances details of low-light regions while maintaining well-balanced luminance and color information. To compare the structure similarity and naturalness, we used the tone mapped image quality index (TMQI). The proposed method maintained better structure similarity in the enhanced image than did the space-variant luminance map (SVLM) method or the adaptive and integrated neighborhood dependent approach for nonlinear enhancement (AINDANE). The proposed method required the smallest computation time among the three algorithms. The proposed method can be easily implemented using the field-programmable gate array (FPGA), with low hardware resources and with better performance in terms of similarity.

• KIEAE Journal
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• v.17 no.3
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• pp.91-97
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• 2017

Purpose: Various studies on a light shelf are in progress, but it has the problem of glare occurrence. The present study suggested a diffusion film as the method for resolving the glare problem, and aimed to establish light shelf-related basic data by conducting the performance evaluation of a light shelf depending on the installation position of the diffusion film. Method: To carry out the light shelf performance evaluation depending on the diffusion film installation position, three cases were established: no diffusion film installation (Case 1), diffusion film installation on the reflector (Case 2), and diffusion film installation on the upper glass surface of the window for light shelf installation (Case 3); and the energy reduction performance, luminance, and luminance contrast were analyzed based on a testbed. Result: The conclusions of this study are as follows. 1) When the diffusion film was applied, the amount of light introduced through the light shelf decreased, and the average indoor illumination decreased accordingly. 2) For Case 3, the lighting energy reduction performance was identical to the lighting energy reduction efficiency of the existing light shelf; and for Case 2, it was found to be inappropriate as the lighting energy consumption increased compared to that of the existing light shelf. 3) The analysis of the glare for the cases established in this study showed that the luminance contrast was low for Case 3, and thus the glare problem could be minimized. 4) The specific angle of the light shelf could induce the glare problem by increasing the luminance depending on the external condition. 5) Based on the aforementioned contents, the installation position of the diffusion film for improving the lighting performance and glare problem of the light shelf was found to be the upper glass surface of the window for light shelf installation.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.129-142
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• 2015

PURPOSES : The purpose of this study is to suggest a basis for setting appropriate safety goals specifically related to the threshold zone luminance in a vehicular traffic tunnel. METHODS : In the test, drivers were divided into two groups. One group consisted of all drivers (average drivers) group with an age ratio of drivers holding domestic driver's license and driver group by age to produce threshold zone luminance in the tunnel. The threshold zone luminance produced as a result was used to analyze how it affects the safety level of each driver group and provide a basis for setting an appropriate safety criterion that can be used to determine threshold zone luminance. We used test equipment, test conditions, and ananalysis of threshold zone luminance identical to that reported by ChoandJung(2014) but the values of adaptation luminance in our analys is were expanded to range from100 to $10,000cd/m^2$. RESULTS : Adaptation luminance and threshold zone luminance are found to be related by a quadratic function. The threshold zone luminance needed by older drivers to ensure a certain safety level is significantly higher than that for drivers of other age brackets when adaptation luminance increases. 56% of older drivers are at an increased risk of an accident at the same luminance for which the safety level of average drivers is 75%. The safety level that can be achieved for older drivers increases to above 60% when threshold zone luminance level is set with the goal of attaining a safety level of more than 85% for average drivers. The safety level that can be attained for average drivers is above 90% when the threshold zone luminance is high enough to ensure over 75% in the safety level of older drivers. Results of this study are applicable to highways and others whose designed speed is 100 km/h. CONCLUSIONS : Threshold zone luminance determined on the basis of drivers having average visual ability is of limited value as a performance standard for ensuring the safety of older drivers. Hence, safety level for older drivers should be considered separately from safety levels for drivers with an average ability to avoid risk. Upward adjustment of older drivers' safety level in the process of determining appropriate threshold zone luminance in a vehicular traffic tunnel may bring both tangible and intangible benefit as a result of reducing accidents. However, there is an associated dollar cost arising from installing and operating lights. As a result, the economic impact of these trade-offs should also be considered.

• Journal of the Korean Data and Information Science Society
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• v.15 no.4
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• pp.891-898
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• 2004

An effective video indexing is required to manipulate large video databases. Most algorithms for video indexing have been commonly used histograms, edges, or motion features. In this paper, we propose an efficient algorithm using the luminance projection for video retrieval. To effectively index the video sequences and to reduce the computational complexity, we use the key frames extracted by the cumulative measure, and compare the set of key frames using the modified Hausdorff distance. Experimental results show that the proposed video indexing and video retrieval algorithm yields the higher accuracy and performance than the conventional algorithm.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.3
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• pp.59-66
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• 1995

In this study through a series of the experiments, 1) the preferable luminance values of the CRT screens, 2) the preferable luminance ratios between the CRT screens and its surrounding surfaces are determined. The results are evaluated by the level of satisfaction, and re-examined by the work performance (number of types, rate of errors) and the level of eye fatique (number of blinks, near point distance)

• Proceedings of the Korean Institute of Communication Sciences Conference
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• 1984.10a
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• pp.88-91
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• 1984

In component coding, it si well known that a Luminance edge provides better masking of the noise added to chrominance signals. So we propose an adapive DPCM coding system which provides good performance in chromainance signals by using the effect of this masking.

• Journal of the Institute of Convergence Signal Processing
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• v.6 no.2
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• pp.74-81
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• 2005

As the multimedia data increases, various scene change detection algorithms for video indexing and sequence matching have been proposed to efficiently manage and utilize digital media. In this paper, we propose a robust scene change detection algorithm for video sequences with abrupt luminance variations. To improve the accuracy and to reduce the computational complexity of video indexing with abrupt luminance variations, the proposed algorithm utilizes edge features as well as color features, which yields a remarkably better performance than conventional algorithms. In the proposed algorithm first we extract the candidate shot boundaries using color histograms and then determine using edge matching and luminance compensation if they are shot boundaries or luminance changes. If the scene contains trivial brightness variations, the edge matching and luminance compensation are performed only for shot boundaries. In experimental results, the proposed method gives remarkably a high performance and efficiency than the conventional methods with the similar computational complexity.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.41 no.5
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• pp.35-44
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• 2004

With increase in digitalmedia data, various video indexing and video sequence matching algorithms have been proposed to efficiently manage and utilize digital media. In this paper, we propose a robust video indexing algorithm to detect scene changes for video sequences with abrupt luminance variations and an efficient video sequence matching algorithm for video sequence query. To improve the accuracy and to reduce the computational complexity for video indexing with abrupt luminance variations, the proposed algorithm utilizes edge features as well as color features, which yields a remarkably better performance than conventional algorithms. In the proposed algorithm first we extract the candidate shot boundaries using color histograms and then determine using edge matching and luminance compensation if they are shot boundaries or luminance changes. If the scene contains trivial brighness variations, the edge matching and luminance compensation are performed only for shot boundaries. In experimental results, the proposed method gives remarkably a high performance and efficiency than the conventional methods with the similar computational complexity.