• Journal of Broadcast Engineering
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• v.21 no.3
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• pp.349-356
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• 2016

In this paper, we propose an efficient assignment method that assigns quantization parameter (QP) in accordance with group of picture (GOP) structure given in HEVC encoder. Each video frames can have difference QP values based on given GOP configuration for HEVC encoding. Particularly, for important frames we can assign low QP values, and vice versa. However, there has not been thorough investigation on efficient QP assignment method by far. Even in HEVC reference software encoder, only monotonic QP assignment method is employed. Thus, the proposed method assign adaptive QP values to each GOP so that temporal dynamic activity between GOPs can be exploited. Through the experiment, the proposed method showed a 7.3% gain of compression performance in terms of BD-rate compared to HEVC test model (HM) in low-delay configuration, and outperformed the existing QP assignment study on average.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.46 no.1
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• pp.59-67
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• 2018

In this paper, the test facility for coaxial propellers at low Reynolds developed and validated by measured data. The test equipment was designed to measure the hovering performance of propellers according to distances between the upper/lower propellers. Thrust, torque, rotational speed, vibration, and amperage of upper and lower propellers can be measured separately. The data acquisition system was built to collect signals of sensors, and LabVIEW software was used to control the motor and collect the signal. The hover performance tests of single propellers were preceded for the facility validation, and then the performance values of coaxial propellers were measured according to distances and diameter differences between the upper/lower propellers. The results showed that the high efficiency is achieved at 20%~30% distance between the upper propeller and lower one. The configuration that the upper propeller has shorter diameter than the lower one has the highest efficiency than other configuration.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2004.05a
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• pp.603-606
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• 2004

Automatic test case generation for testing an embedded software is considered. Existing tools for test case generation such as finite state machine or mutant test usually adopt top down approach and depend upon graphical transition and decision table, which makes it difficult to find out where the bugs exist. Also it is hard to describe the special features of embedded systems such as concurrent execution of individual components. Most of embedded systems interacts with the real world, receiving signals through sensors or switches and sending output signals to actuators that somehow manipulate the environment. Embedded software controls the entire system based on the logics such as interpreting the sensor inputs and making the actuators to start or stop their intended operation. This study proposes an automatic test case generation procedure that tests the system starting from the control logics of sensors, switches and actuators and then their concurrent execution controls, and finally the entire system operation. Such a stepwise approach makes it easy to generate test cases to tell where the bugs of embedded software exist.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1680-1691
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• 2009

To improve the quality of healthcare and build up the health delivery system, electronic health record system is important for healthcare institutions providing health services. However, the systems currently operated in domestic healthcare institutions use independent software interface with distributed environment for data search and process. Therefore, it raises an additional expense to buy or develop each interface module when there is a link to new system and the problem of complexity. To solve these problems, this study implemented the service oriented architecture basis for home nursing service and carried out an assessment. The study defined the process modeling and business requirements based on the scenario of service and drew 17 suitable services based on five verification items for service design. To draw the final service, seven services were selected by service litmus test (SLT). The study found that, by the improvement of business process for healthcare service support department, SOA based information system has an effect of time reduction of patient processing time. In conclusion, to enable the hospital information system to cope with various demands of healthcare consumers, it is necessary to consider the application of SOA technology which has excellent interoperability, reusability and maintenance.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.30 no.4
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• pp.573-582
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• 2020

Fuzzing is a method of testing software by randomly generating test cases. Since its introduction, a variety of fuzzing techniques have been studied. Among them, mutation-based fuzzing is an efficient method that finds real-world bugs even though it uses a simple approach such as probabilistic bit-flipping and character substitution. However, the interpreter fuzzing has difficulty in applying general mutation techniques because the interpreter requires grammar and semantic correctness input values. In this paper, we present a novel mutation-based fuzzing on JavaScript interpreters with a dynamic data flow analysis. To this end, we implement JMFuzzer that can generate various types of mutated test cases that operate normally without runtime errors in JavaScript interpreter considering syntax and semantics. As a result, we found numerous unknown vulnerabilities in the latest JavaScript interpreters. We reported all of them to the vendors.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.4
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• pp.940-947
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• 2015

This paper presents the region of interest pattern image extraction method on a display printed matrix pattern. Proposed method can not use conventional method such as laser, ultrasonic waves and touch sensor. It searches feature point and rotation angle using luminance and pattern reliable feature points of input image, and then it extracts region of interest. In order to extract region of interest, we simulate proposed method using pattern image written various angles on display panel. The proposed method makes progress using the OpenCV and the window program, and was designed using Verilog-HDL and was verified through the FPGA Board(xc6vlx760) of Xilinx.

• KIPS Transactions on Software and Data Engineering
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• v.3 no.12
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• pp.537-546
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• 2014

The purpose of this study is to develope an algorithm which generates trip plans based on rating points of travel app users and travel experts to help potential travellers experience their desired destinations in advance. This algorithm uses the above rating points and the gradually created hierarchy to generate the most preferred and efficient trip courses. Users can go through video clips or panoramic VR videos of the actual destinations from their trip plans generated by the algorithm which may add excitement to their actual trips. With our heuristic methods, the more users input their ratings, the better trip plans can be generated. This algorithm has been tested on android OS and proven efficient in generating trip plans. This research introduces a way to experience travel destinations with panoramic VR video and proposes the algorithm which generates trip plans based on users' ratings. It is expected to be useful for travellers' trip planning and to contribute growth in the travel market.

• Journal of KIISE:Software and Applications
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• v.34 no.2
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• pp.104-111
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• 2007

This paper examines how the performance of an automatic speech recognizer was improved for Korean Point-of-Interest (POI) data by modeling pronunciation variation using structural prosodic information such as prosodic words and syllable length. First, multiple pronunciation variants are generated using prosodic words given that each POI word can be broken down into prosodic words. And the cross-prosodic-word variations were modeled considering the syllable length of word. A total of 81 experiments were conducted using 9 test sets (3 baseline and 6 proposed) on 9 trained sets (3 baseline, 6 proposed). The results show: (i) the performance was improved when the pronunciation lexica were generated using prosodic words; (ii) the best performance was achieved when the maximum number of variants was constrained to 3 based on the syllable length; and (iii) compared to the baseline word error rate (WER) of 4.63%, a maximum of 8.4% in WER reduction was achieved when both prosodic words and syllable length were considered.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.36 no.2
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• pp.185-194
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• 2008

In this paper, an efficient technique is proposed to integrate the 3D user interface with the tiled display system in PC cluster environment. In the developed 3D user interface software, various menus are provided to increase the user friendliness of the interface, including the several model-control-commands. To eliminate the noise produced from the 3D user interface devices, the box filtering algorithm is employed. Further, a communication splitting algorithm, which is a kind of asynchronous communication method, is proposed to reduce the motion delay between the 3D interface and the tiled display system, and its efficiency is validated through the benchmarking tests.

• Journal of Astronomy and Space Sciences
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• v.12 no.1
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• pp.78-89
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• 1995

We solved n-body problem about 9 planets, moon, and 4 minor planets with relativistic effect related to the basic equation of motion of the solar system. Perturbations including flgure potential of the earth and the moon and solid earth tidal effect were considered on this relativistic equation of motion. The orientations employed precession and nutation for the earth, and lunar libration model with Eckert's lunar libration model based on J2000.0 were used for the moon. Finally, we developed heliocentric ecliptic position and velocity of each planet using this software package named the SSEG (Solar System Ephemerides Generator) by long-term (more than 100 years) simulation on CRAY-2S super computer, through testing each subroutine on personal computer and short-time(within 800 dyas) running on SUN3/280 workstation. Epoch of input data JD2440400.5 were adopted in order to compare our results to the data archived from JPL's DE 200 by Standish and Newhall. Above equation of motion was integrated numerically having 1-day step-size interval through 40,000 days (about 110 years long) as total computing interval. We obtained high-precision ephemerides of the planets with maximum error, less $than\pm2\times10^{-8}AU(\approx\pm3km)$ compared with DE200 data (except for mars and moon).