• Journal of the Institute of Electronics Engineers of Korea TC
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• v.40 no.12
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• pp.27-37
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• 2003

In the next generation Internet(NGI) based on dense wavelength division multiplexing(DWDM) technology, QoS RWA considering various QoS parameters of DWDM networks is regard as one of the key issues in providing real-time multimedia services. However, finding a qualified path meeting multi-constraints is generally NP-complete problem. It is insufficient for QoS RWA researches in DWDM networks that must consider QoS parameter as well as wavelength-continuity constraint. This paper proposes qualified path routing (QPR) algorithm with minimum computation and implementation complexity based on flooding method to accomplish QoS routing and wavelength assignment (RWA). We also introduce a QoS-based RWA mechanism considering multi-constraint such as optical signal quality attributes, survivability and wavelength-continuity constraint combined with proposed routing algorithm. Simulation results show superior efficiency of the proposed algorithms in terms of blocking probability, routing overhead and survivability ratio.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.1
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• pp.166-175
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• 2017

Hazardous volcanic activity will continue to occur in the ring of fire, a major area in the basin of the Pacific Ocean where a large number of earthquakes and volcanic eruptions occur. and, because of rising populations, development pressures, and expanding national and international air traffic over volcanic regions, risks to life and property through exposure to volcano hazards continue to increase. During an eruption, volcanic contamination can reach and exceed the cruising altitudes of turbine-powered aircraft, among others, within minutes and spread over vast geographical areas within a few days. Volcanic ash can affect the operation of aircraft at aerodromes. Volcanic ash deposition at an aerodrome, even in very small amounts, can result in the closure of the aerodrome until all the deposited ash has been removed. In this study, air traffic information framework is presented along with algorithms to define affected routes, waypoints and airports using GIS geometry analysis.

• Journal of IKEEE
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• v.11 no.4
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• pp.187-192
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• 2007

Since wireless sensor networks (WSN) have relatively narrow bandwidth and have limited memory space. Mosaic by inlaying images transmitted by adjacent sensors can provide wider field of view and smaller storage memory. Most WSN are used for surveillance purpose, image acquisition period should be sufficiently short, so that mosaic algorithm has to be run in real time. Proposed algorithm is derived by using the fact that position of sensor nodes are fixed and known. Transformation matrix can be calculated by using distance between sensor nodes and distance between sensor nodes and predefined object. Simulation result shows that proposed algorithm provides very short processing time whereas it preserves image quality.

• Journal of the Institute of Electronics Engineers of Korea SP
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• v.45 no.4
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• pp.1-9
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• 2008

This paper presents a rapid watermarking algorithm based on DC image, which provides a resilience to geometric distortion. Our proposed scheme is based on $8{\times}8$ block DCT that is widely used in image/video compression techniques (e.g., JPEG and MPEG). In particular, a DC image is analyzed by DWT to embed a watermark. To overcome a quality degradation caused by a watermark insertion into DC components, we discern carefully the intensity and amount of watermark along the different subbands of DWT. Note that the proposed technique supports a high throughput for a real-time watermark insertion and extraction by relying on a partial decoding (i.e., DC components) on $8{\times}8$ block DCT domain. Experimental result shows that the proposed watermarking scheme significantly reduces computation time of 82% compared with existing DC component based algorithm and yet provides invariant properties against various attacks such as geometric distortion and JPEG compression, etc.

• KIISE Transactions on Computing Practices
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• v.21 no.2
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• pp.138-143
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• 2015

The Boyer-Moore algorithm is a single pattern string matching algorithm that is widely used in various applications such as computer and internet security, and bioinformatics. This algorithm is computationally demanding and requires high-performance parallel processing. In this paper, we propose a parallelization and performance optimization methodology for the BM algorithm on a GPU. Our methodology adopts an algorithmic cascading technique. This results in significant reductions in the mapping overheads for the threads participating in the parallel string matching. It also results in the efficient utilization of the multithreading capability of the GPU which improves the load balancing among threads. Our experimental results show that this approach achieves a 45-times speedup at maximum, in comparison with a serial execution.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.41 no.12
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• pp.1844-1850
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• 2016

The bilateral filter can reduce the noise while preserving details computing the filtering output at each pixels as the average of neighboring pixels. In this paper, we propose a real-time system based on window division. Overall performance is increased due to the parallel architectures which computes five rows in the kernel window simultaneously but with pipelined scheduling. We consider the tradeoff between the filter performance and the hardware cost and the bit allocation has been determined by PSNR analysis. The proposed architecture is designed with verilogHDL and synthesized using Dongbu Hitek 110nm standard cell library. The proposed architecture shows 416Mpixels/s (397fps) of throughput at 416MHz of operating frequency with 132K gates.

• Journal of the Korean Society for Nondestructive Testing
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• v.26 no.2
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• pp.108-114
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• 2006

Transient and asymmetric density distributions of butane flow have been investigated from laser image signals by developed three-dimensional digital speckle tomography. Moved signals of speckles have been captured by multiple CCD images in three angles of view simultaneously because the flows were asymmetric and transient. The signals of speckle movements between no flow and downward butane flow from a circular half opening have been calculated by a cross-correlation tracking method so that those distances can be transferred to deflection angles of laser rays fur density gradients. The three-dimensional density fields have been reconstructed from the fringe shift signal which is integrated from the deflection angle by a real-time multiplicative algebraic reconstruction technique (MART).

• Smart Media Journal
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• v.7 no.1
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• pp.31-36
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• 2018

In this paper, we propose automatic screen on / off method of OST-HMD screen using gaze depth estimation technique. The proposed method uses MLP (Multi-layer Perceptron) to learn the user's gaze information and the corresponding distance of the object, and inputs the gaze information to estimate the distance. In the learning phase, eye-related features obtained using a wearable eye-tracker. These features are then entered into the Multi-layer Perceptron (MLP) for learning and model generation. In the inference step, eye - related features obtained from the eye tracker in real time input to the MLP to obtain the estimated depth value. Finally, we use the results of this calculation to determine whether to turn the display of the HMD on or off. A prototype was implemented and experiments were conducted to evaluate the feasibility of the proposed method.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1043-1051
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• 2008

In polyolefin processes melt index (MI) is the most important controlled variable indicating product quality. Because of the difficulty in the on-line measurement of MI, a lot of MI estimation and correlation methods have been proposed. In this work a new dynamic MI estimation scheme is developed based on system identification techniques. The empirical MI estimation equation proposed in the present study is derived from the $1^{st}$-order dynamic models. Effectiveness of the present estimation scheme was illustrated by numerical simulations based on plant operation data including grade change operations in high density polyethylene (HDPE) processes. From the comparisons with other estimation methods it was found that the proposed estimation scheme showed better performance in MI predictions. Using the model predictive control method based on the present dynamic MI estimation model, MI values are estimated and compared with those of MI setpoints. From the numerical simulation of the proposed control system, it was found that significant reduction of transition time and the amount of off-spec during grade changes were achieved.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.10B
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• pp.1076-1085
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• 2009

In this paper, a new method for efficient computation of CGH patterns for 3-D video images is proposed by combined use of temporal redundancy and look-up table techniques. In the conventional N-LT method, fringe patterns for other object points on that image plane can be obtained by simply shifting these pre-calculated PFP (Principle Fringe Patterns). But there have been many practical limitations in real-time generation of 3-D video holograms because the computation time required for the generation of 3-D video holograms must be massively increased compared to that of the static holograms. On the other hand, as ordinary 3-D moving pictures have numerous similarities between video frames, called by temporal redundancy, and this redundancy is used to compress the video image. Therefore, in this paper, we proposed the efficient hologram generation method using the temporal redundancy of 3-D video image and N-LT method. To confirm the feasibility of the proposed method, some experiments with test 3-D videos are carried out, and the results are comparatively discussed with the conventional methods in terms of the number of object points and computation time.