• The Journal of Korean Institute of Communications and Information Sciences
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• v.23 no.8
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• pp.2120-2130
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• 1998

This paper concerns a design of programmable MPEG decoder for video processing by object unit on network. The decoder can process video data effectively by a embedded controller with stack buffers for supporting OOP (Object-Oriented Programming). The controller offers extended instructions that process several data types including 32bit integer type. In addition to that, we have a vector processor, in this decoder that can execute advanced compensation and prediction by half pixel and SA(Shape Adaptive)-IDCT of MPEG-4. Absolutors and halfers in the vector processor make this architecture extensive to a encoder. We verified the decoder with $0.6\mu\textrm{m}$ 5-Volt CMOS COMPASS library.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.2
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• pp.445-452
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• 2010

In this paper, an attempt has been made to design the controller applicable for H.264 level3 encoder of baseline profile on full hardware basis. The designed controller module first stores the images supplied from CMOS Image Sensor(CIS) at main memory, and then reads or stores the image data in macroblock unit according to encoder operation. The timing cycle of the DMA controller required to process a macroblock is 478 cycles. In order to verify the our design, reference-C encoder, which is compatible to JM 9.4, is developed and the designed controller is verified by using the test vector generated from the reference C code. The number of cycle in the designed DMA controller is reduced by 40% compared with the cycle of using Xilinx MIG.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.10
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• pp.1467-1472
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• 2014

This paper study on powering characteristic on speed variation of propulsion system of prototype 8200 electric locomotive propulsion system through simulation modeling. For this purpose, it being applied in the field of railway IGBT (Insulated Gate Bipolar Transistor) elements are used. Converter was performed PLL (Phase-Locked Loop) control method that is used to control the phase and output voltage, and the inverter was carried an indirect vector control method to control the speed of traction motor. The results of simulation by modeling and experimental unit, we was confirmed that converter is controlled a unity power factor and output voltage by reference voltage. Also traction motor was controlled by indirect vector control and SVPWM inverter switching method very well.

• Journal of Korea Multimedia Society
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• v.10 no.5
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• pp.559-568
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• 2007

Anchor-person scene detection is of significance for video shot semantic parsing and indexing clues extraction in content-based news video indexing and retrieval system. This paper proposes an efficient algorithm extracting anchor ranges that exist in sports news video for unit structuring of sports news. To detect anchor person scenes, first, anchor person candidate scene is decided by DCT coefficients and motion vector information in the MPEG4 compressed video. Then, from the candidate anchor scenes, image processing method is utilized to classify the news video into anchor-person scenes and non-anchor(sports) scenes. The proposed scheme achieves a mean precision and recall of 98% in the anchor-person scenes detection experiment.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.4
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• pp.173-183
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• 2022

The objective of this research is to examine the influence of the COVID-19 pandemic on stock markets in a few developing and developed countries. This study uses daily data from January 2020 to May 2021 and obtained from World Health Organization and Thomson Reuters. The secondary data was evaluated through panel econometric methodology that includes different unit root tests, and to analyze the long-run relationship between variables, panel cointegration techniques were applied. The long-run causality among variables was examined through Panel Vector Error Correction Model. The overall findings of this study suggest a long-run association exists between several cases and death with the stock returns of the GCC and other stock markets. Furthermore, the VECM model also identified a long-run causality running from COVID cases and death towards the stock rerun of both sets of stock markets. However, a subsequent Wald test yielded mixed results, indicating no short-run causality between cases and deaths and stock returns in both groups; however, in the case of GCC, several COVID-19 cases are having a causal impact on stock markets, which is notable in light of the fact that the death rate in GCC is significantly lower than in many developed and developing countries.

• Journal of Astronomy and Space Sciences
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• v.38 no.2
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• pp.145-155
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• 2021

In this work, preliminary launch opportunities from NARO Space Center to the Sun-Earth Lagrange point are analyzed. Among five different Sun-Earth Lagrange points, L1 and L2 points are selected as suitable candidates for, respectively, solar and astrophysics missions. With high fidelity dynamics models, the L1 and L2 point targeting problem is formulated regarding the location of NARO Space Center and relevant Target Interface Point (TIP) for each different launch date is derived including launch injection energy per unit mass (C3), Right ascension of the injection orbit Apoapsis Vector (RAV) and Declination of the injection orbit Apoapsis Vector (DAV). Potential launch periods to achieve L1 and L2 transfer trajectory are also investigated regarding coasting characteristics from NARO Space Center. The magnitude of the Lagrange Orbit Insertion (LOI) burn, as well as the Orbit Maintenance (OM) maneuver to maintain more than one year of mission orbit around the Lagrange points, is also derived as an example. Even the current work has been made under many assumptions as there are no specific mission goals currently defined yet, so results from the current work could be a good starting point to extend diversities of future Korean deep-space missions.

• The Journal of Asian Finance, Economics and Business
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• v.9 no.1
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• pp.189-201
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• 2022

The study empirically examines the impact of monetary fundamentals along with global oil prices on the Pak-rupee exchange rate using the monthly data over 2001-2020. Employing the cointegrating vector autoregressive with exogenous variables (VARX) and vector error correction model with exogenous variables (VECMX), the study analyzes the impact of domestic monetary fundamentals while considering the foreign variables as weakly exogenous. In order to account for the structural breaks in the data, the Lagrange multiplier (LM) unit root test with two structural breaks has been used (Lee & Strazicich, 2003). The empirical results reveal that the domestic and foreign monetary variables significantly explain the exchange rate movements in Pakistan both in the long run and in the short run. The dynamic properties of the monetary model of exchange rate have been analyzed using the persistence profile analysis and generalized impulse response functions (GIRFs). The results reveal that the responses of shocks to domestic monetary fundamentals are consistent with the predictions of the monetary model of the exchange rate. Furthermore, being a net oil importer, a rise in global oil prices significantly depreciated the Pak-rupee exchange rate over the period of study. The global financial crisis (GFC) and pandemic (COVID-19) were also found to cause the Pak-rupee exchange rate depreciation.

• Journal of IKEEE
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• v.27 no.4
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• pp.636-643
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• 2023

In this paper, a high-speed calibration method for phased array antennas in the far-field is presented A max calibration, which is a simplification of the rotating-element electric-field vector (REV) method that calibrates each antenna element only through received power, and a method of grouping calibrations by sub-array unit rather than each antenna element were proposed. Using the Proximal Policy Optimization (PPO) algorithm, we found a partitioning optimized for the distribution of phased array antennas and calibrated it on a subarray basis. An adaptive max calibration method that allows faster calibration than the conventional method was proposed and verified through simulation. Not only is the gain of the phased array antenna higher while calibration is being made to the target, but the beam pattern is closer to the ideal beam pattern than the conventional method.

• Journal of Astronomy and Space Sciences
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• v.40 no.3
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• pp.123-129
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• 2023

This paper presents an analysis of the trans-lunar trajectory insertion performance of the Korea Pathfinder Lunar Orbiter (KPLO), the first lunar exploration spacecraft of the Republic of Korea. The successful launch conducted on August 4, 2022 (UTC), utilized the SpaceX Falcon 9 rocket from Cape Canaveral Space Force Station. The trans-lunar trajectory insertion performance plays a crucial role in ensuring the overall mission success by directly influencing the spacecraft's onboard fuel consumption. Following separation from the launch vehicle (LV), a comprehensive analysis of the trajectory insertion performance was performed by the KPLO flight dynamics (FD) team. Both orbit parameter message (OPM) and orbit determination (OD) solutions were employed using deep space network (DSN) tracking measurements. As a result, the KPLO was accurately inserted into the ballistic lunar transfer (BLT) trajectory, satisfying all separation requirements at the target interface point (TIP), including launch injection energy per unit mass (C3), right ascension of the injection orbit apoapsis vector (RAV), and declination of the injection orbit apoapsis vector (DAV). The precise BLT trajectory insertion facilitated the smoother operation of the KPLO's remainder mission phase and enabled the utilization of reserved fuel, consequently significantly enhancing the possibilities of an extended mission.

• Asia-Pacific Journal of Business Venturing and Entrepreneurship
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• v.10 no.3
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• pp.133-146
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• 2015

This study is to investigate the causal relationship between exchange hedge and the net income of the shipbuilder through the unit root test and co-integration and vector autoregressive model(Vector Autoregressive Model: VAR). First, quarter net income of shipbuilders to order a unit root tests from 2000 to 2013 was used as a value after the Johnson transformation. In the same period, the return on bond futures(KTBF), three years bond yield(KTB3Y), America-Korea exchange differences are weekly data for each quarterly difference in value was converted by utilization, shipbuilding shares after log transformation which it was used. Also, structural change point investigation analysis to verify that looked to take advantage of the structural changes occur in the exchange hedge strategies affecting net income in the shipbuilding industry. Between the exchange hedge and net income of shipbuilders in structural change points detection and analysis showed that structural changes occur starting in 2004. In other words, strategy of shipbuilders about exchange hedge has occurred from "passive exchange hedge" to "active exchange hedge". The exchange hedge of the Korea shipbuilders through the estimation of the VAR was able to grasp that affect the profitability of mutual shipbuilders. Macroeconomic variables and stock prices could also check to see that affected the net income of the shipbuilding industry.