• KSII Transactions on Internet and Information Systems (TIIS)
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• v.6 no.11
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• pp.2827-2848
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• 2012

Previously, we described a social media cloud computing service environment (SMCCSE). This SMCCSE supports the development of social networking services (SNSs) that include audio, image, and video formats. A social media cloud computing PaaS platform, a core component in a SMCCSE, processes large amounts of social media in a parallel and distributed manner for supporting a reliable SNS. Here, we propose a Hadoop-based multimedia system for image and video transcoding processing, necessary functions of our PaaS platform. Our system consists of two modules, including an image transcoding module and a video transcoding module. We also design and implement the system by using a MapReduce framework running on a Hadoop Distributed File System (HDFS) and the media processing libraries Xuggler and JAI. In this way, our system exponentially reduces the encoding time for transcoding large amounts of image and video files into specific formats depending on user-requested options (such as resolution, bit rate, and frame rate). In order to evaluate system performance, we measure the total image and video transcoding time for image and video data sets, respectively, under various experimental conditions. In addition, we compare the video transcoding performance of our cloud-based approach with that of the traditional frame-level parallel processing-based approach. Based on experiments performed on a 28-node cluster, the proposed Hadoop-based multimedia transcoding system delivers excellent speed and quality.

• The Journal of the Korea institute of electronic communication sciences
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• v.7 no.3
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• pp.485-490
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• 2012

In this paper, driver circuit of LED lights for ships is designed and implemented to replace conventional lights with filament which have short life time due to vibration of ships. The driver of LED module is switching circuit without transformer to reduce volume and cost. As switch circuit controls input 220 VAC with PWM, LED module is reliably driven. Power factor is improved by using valley-fill PFC compensation circuit which is handled to pulse current of switching circuit. Serial-parallel LED circuit is applied to reduce change period of lights of long-term navigation ships. Array of serial-parallel can operate even if some of LEDs is damaged. It is suitable for ships that power consumption and power factor of lights including developed drive circuit have 39Watt and 0.925 respectively.

• Aerospace Engineering and Technology
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• v.3 no.2
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• pp.11-19
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• 2004

A software-controlled unregulated bus system in which the main bus is directly connected to a battery and the duty-ratio for PWM switch is controlled by the on-board satellite software, is usually used for LEO satellites. This paper proposes a new power-stage circuit that can be available for modularization of a power regulator which is used at the software-controlled unregulated bus system satellite. And we analyze the proposed power-stage operation according to its operating modes and verify it by performing software simulation and hardware experiment using prototype. We construct a parallel-module converter which is composed of the proposed power-stage and perform experiment to verify modular characteristics of the proposed power-stage. Finally, we verify the usefulness of the proposed power-stage by comparing above results with those of a parallel-module converter made of conventional power-stage.

• International Journal of Highway Engineering
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• v.15 no.6
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• pp.41-47
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• 2013

PURPOSES : The purpose of this study is about noise which is generated from roads and is consist of irregular frequency variation from low frequency to various band. The existing methods of noise reduction are sound barrier that uses insulation material and absorbing material or have applied passive technology of noise reduction by devices. The total frequency band is needed to apply active noise control. METHODS : In this study applies to the field of road traffic environment, signal processing controller and various analog signal input/output, the amplifier module is based on parallel-core embedded processor designed. DSP performs the control algorithm of the road traffic noise. Noise sources in the open space performance of evaluation were applied. In this study, controller of active signal processor was designed based on the module of audio input/output and main controller of embedded process. The controller of active signal processor operates noise reduction algorithm and performance tests of noise reduction in inside and outside environment were executed. RESULTS : The signal processing controller with OMAP-L137 parallel-core processors as the center, DSP processors in the active control operations dealt with quickly. To maximize the operation speed of an object and ARM processor is external function keys and display for functions and evaluating the performance management system was designed for the purpose of the interface. Therefore the reduction of road traffic noise has established an electronic controller-based noise reduction. CONCLUSIONS : It is shown that noise reduction is effective in the case of pour tonal sound and complex tonal sound below 500Hz by appling to Fx-LMS.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.12
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• pp.2140-2145
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• 2008

We design and synthesize a 128-point FFT processor for multi-band OFDM, which can be applied to a UWB transceiver. The structure of a 128-point FFT processor is based on a Radix-2 FFT algorithm and a R2SDF pipeline architecture. The algorithm is efficiently modeled in VHDL and the result is simulated using Modelsim. Finally, they are synthesized on Xilinx Vertex-II FPGA, and an operational frequency of 18.7MHz has been obtained. It is expected that the proposed 128-point FFT processor can be applied to an entire FFT block as one of parallel processed FFTs. In order to obtain the enhanced maximum frequency of operation, we design the FFT module consisting of four 128-point FFT processors for parallel process. As a result, we achieve the performance requirement of computing the FFT module in multi-band OFDM symbol timing in 90nm ASIC process.

• Journal of Information Processing Systems
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• v.14 no.6
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• pp.1445-1456
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• 2018

Environment perception and three-dimensional (3D) reconstruction tasks are used to provide unmanned ground vehicle (UGV) with driving awareness interfaces. The speed of obstacle segmentation and surrounding terrain reconstruction crucially influences decision making in UGVs. To increase the processing speed of environment information analysis, we develop a CPU-GPU hybrid system of automatic environment perception and 3D terrain reconstruction based on the integration of multiple sensors. The system consists of three functional modules, namely, multi-sensor data collection and pre-processing, environment perception, and 3D reconstruction. To integrate individual datasets collected from different sensors, the pre-processing function registers the sensed LiDAR (light detection and ranging) point clouds, video sequences, and motion information into a global terrain model after filtering redundant and noise data according to the redundancy removal principle. In the environment perception module, the registered discrete points are clustered into ground surface and individual objects by using a ground segmentation method and a connected component labeling algorithm. The estimated ground surface and non-ground objects indicate the terrain to be traversed and obstacles in the environment, thus creating driving awareness. The 3D reconstruction module calibrates the projection matrix between the mounted LiDAR and cameras to map the local point clouds onto the captured video images. Texture meshes and color particle models are used to reconstruct the ground surface and objects of the 3D terrain model, respectively. To accelerate the proposed system, we apply the GPU parallel computation method to implement the applied computer graphics and image processing algorithms in parallel.

• Journal of the Semiconductor & Display Technology
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• v.20 no.1
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• pp.77-82
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• 2021

Using a multi-array needle module developed for coating of high-density cylindrical microlens array (C-MLA), we have fabricated an anti-Moiré filter for LED screens. The Moiré phenomenon appears due to the interference between the array pattern of image sensors in a camera and the non-emission area (grid pattern) of a LED screen. To suppress it, we have employed poly(methyl methacrylate) (PMMA) and coated it on a glass substrate in the form of a grid and non-grid (parallel lines). We have rotated the needle module in order to increase the number of C-MLAs. With this scheme, we have fabricated the 150 mm × 150 mm anti-Moiré filters where 836 microlens lines are formed. They show the average width of 255.4 ㎛, the average distance between CMLs of 94.6 ㎛, and C-MLA width non-uniformity of 4.7%. We have shown that the Moiré patterns still appear in the presence of the parallel (non-grid)-type filter, whereas they disappeared completely by the grid-type filter. It is due to the fact that the Moiré patterns are diffused more effectively by the grid-type C-MLA.

• Journal of the Korean Society of Clothing and Textiles
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• v.21 no.4
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• pp.769-781
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• 1997

The purpose of this research is to show how to use the patternist's CAD system in order to make design patterns efficiantly. Using the PAD System Technologies company's PAD System Module, which is very officiant in designing patterns, the basic pattern or design pattern can be designed and applyed to the Sample Module, thus, then it could manufacture, retouch or choose a model, making it posible to go to the next level which is seam patterns for industrial use. By understanding the change of the design that is chosen through the design pattern making and Sample Module process', this study is presentated a plan on how to utilize the patternist's working adaption ability by the CAD system, and also considered the problems in using it. Ability of Design Confrontation of CAD System: 1) The result of an operation can be saved and retouched. On a saved list the patterns can be chosen and changed, thus, making it posible to complete a design very quickly. 2) When sewing every designed pattern in Sample Module, the model can be operated merely by selecting each sewing position, thus creating the same effect of a designer's muslin sample process in a much lesser time. Point at issue in the utilization CAD system: 1) When combining two darts into one place the amounts of darts that are already these have to be erasers, and then, the two darts points are moved that place, thus, containing them, which is very conplicated. 2) When making a gathering, because system can only be recognized in a opend line, the pattern should be separated in order to put a gathering inside a pattern. 3) In order to readjust the amounte of dart. The dart is erased first and then made new dart again. 4) When making tucks in a Sample Module, the form that gets narrow towards the pivot point can not be recognized so the sewing lines of the tucks is adjusted into parallel lines. 5) The Sample Module 3D operation can not attach the bodice to the shirts, instead they become fixed into each other. In the case of shoulder line tucks the amounts of pleats can not be expanded draperary naturally, thus, making it hard to showing the silhouette accurately. If these problems are solved, especially if the silhouette of a model can be created to have natural drapery in the 3D Module, models can be shown on the screen in possible to compare and examine even a change of a detail, by designing this 3D Module Production sample process will be more effective, thus, making the CAD system more useful in sewing design process.

• Journal of KIISE:Software and Applications
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• v.32 no.5
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• pp.366-377
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• 2005

We find a module may that takes optimal correction rate of Korean spelling corrector. If there are a lot of module numbers of spelling corrector, it is difficult to calculate optimal correction rate of spelling corrector because permutation of N-modules is N!. This Korean spelling corrector consists of 19 modules. It is impossible to arrange 19 modules actually and the correction rate is various according to input data. We found the range of correction rate using parallel processing between modules and the optimal correction rate using sequential processing of modules. Input data that are used in an experiment is 753,191 eojeol's sets that happen in newspaper publishing company during several years. About this error set, theoretical maximum correction rate of spelling corrector is $97.28\%$ (732,764/753,191). But we got the optimal correction rate $96.62\%$ (727,750/733,191). This optimal correction rate is almost near to $99.31\%$ (727,750/732,764) of the maximum correction rate.

• The Transactions of the Korean Institute of Power Electronics
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• v.22 no.4
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• pp.360-368
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• 2017

This paper proposes the 80-kW high-efficiency bidirectional hybrid SiC boost/buck converter using droop control for DC nano-grid. The proposed converter consists of four 20-kW modules to achieve fault tolerance, ease of thermal management, and reduced component stress. Each module is constructed as a cascaded structure of the two basic bi-directional converters, namely, interleaved boost and buck converters. A six-pack hybrid SiC intelligent power module (IPM) suitable for the proposed cascaded structure is adopted for high-efficiency and compactness. The proposed converter with hybrid switching method reduces the switching loss by minimizing switching of insulated gate bipolar transistor (IGBT). Each module control achieves smooth transfer from buck to boost operation and vice versa, since current controller switchover is not necessary. Furthermore, the proposed parallel control using DC droop with secondary control, enhances the current sharing accuracy while well regulating the DC bus voltage. A 20-kW prototype of the proposed converter has been developed and verified with experiments and indicates a 99.3% maximum efficiency and 98.8% rated efficiency.