• Journal of Korea Game Society
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• v.4 no.3
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• pp.65-70
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• 2004

The conventional 3D graphic accelerator is mainly focused on high performance in the application area of computer graphic and 3D video game How ever the existing 3D architecture is not suitable for portable devices because of its huge power. So, we analyze the embedded 3D graphics renderer. After the analyzing, to reduce the power, triangle set-up stage and edge walking stage are executed sequentially while scan-line processing stage and span processing stage which control performance of 3D graphic accelerator are executed parallel.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.6
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• pp.539-545
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• 2010

Through the AUTOSAR methodology, the embedded software shall become more flexible, reusable, maintainable than ever. However, it is not mentioned about specific timing constraints of software components in AUTOSAR. There are a few basic principles for mapping runnable entities. At this point, AUTOSAR software design with optimal scheduling method is one of the enabling technologies in vehicle embedded system. This paper presents an approach based on mapping runnable entities and task scheduling design method for EPS (Electric Power Steering) software components, based on AUTOSAR. In addition, the experimental results of concurrent simulation show that the proposed scheduling technique and timing synchronization in the software component design can achieve the improved torque ripple performance and it well suited for EPS application software.

• ETRI Journal
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• v.29 no.4
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• pp.463-469
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• 2007

A phase-locked loop (PLL) is described which is operable from 0.4 GHz to 1.2 GHz. The PLL has basically the same architecture as the conventional analog PLL except the locking information is stored as digital code. An analog-to-digital converter is embedded in the PLL, converting the analog loop filter output to digital code. Because the locking information is stored as digital code, the PLL can be turned off during power-down mode while avoiding long wake-up time. The PLL implemented in a 0.18 ${\mu}m$ CMOS process occupies 0.35 $mm^2$ active area. From a 1.8 V supply, it consumes 59 mW and 984 ${\mu}W$ during the normal and power-down modes, respectively. The measured rms jitter of the output clock is 16.8 ps at 1.2 GHz.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.642-649
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• 2006

In order to recognize a situation from a environment which provides an intelligent service, we propose state-transition based situation modeling which is suitable for a low computing power and restricted resources like embedded systems, and we designed its application to a situation-action converter(SAC)which is consist of two parts; situation detector recognized wanted situations and action generator generated various control actions. Then, we implemented a situation manager for smart scheduler service by using a SAC which is installed to a ARM processor based embedded Linux evaluation board.

• Journal of Electrical Engineering and Technology
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• v.10 no.1
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• pp.388-394
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• 2015

The inrush current of a large inductive load can be reduced with a soft starter; however, the large inrush current caused by simultaneous bulk starts (SBSs) cannot be effectively reduced. In order to reduce the high inrush current and voltage sag owing to the SBSs of large capacity inductive loads within a power network, a novel hybrid sequential start control system is proposed, implemented on embedded systems, and evaluated with a testbed in this study. From the experimental and simulation results of the proposed control system, the inrush current could be effectively restricted below the maximum current capacity of a power distributing board. Moreover, with the proposed system, power cost typically dictated by the peak power consumption can be fairly reduced, and the quality of the power system connected to the inductive loads can be efficiently increased.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.11
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• pp.1827-1834
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• 2016

This paper presents a high efficient generator with PM(Permanent Magnet) exciter. The proposed PM exciter for the generator can produce a linear output voltage according to the engine speed. This output voltage is directly used to control the field current of the generator to adjust the generator output voltage. In the proposed generator system, since the field winding current can be supplied by the PM exciter, the generator can self-start without any battery or an external power supply due to the low residential flux. Furthermore, the operating efficiency of the generator is higher than a conventional winding exciter. The main problem of the proposed generator system, the field winding current controller has to be embedded inside the generator, and it rotates according to the generator shaft. In this paper, the proper embedded current controller is designed for the proposed generator system. Due to the embedded controller cannot be connected to the outside the generator controller, the measured instantaneous output voltage of the generator is transferred by the photo isolated communication using shaft aligned infrared transmitter and receiver to keep the constant generator output voltage. In this paper, 10kW, 380V engine generator with PM exciter and the embedded DAVR(Digital Automatic Voltage Regulator) are described. The proposed high efficiency generator is simulated and tested to verify the effectiveness.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.16-21
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• 2011

Since the maximum power operating point(MPOP) of PCS alters with changing atmospheric conditions temperature conditions shadow conditions it is important to operate for PCS to keep maximum power point tracking(MPPT) continuously. This paper presents the results of modeling PV system by PSIM simulator and investigates the influence on the PV system from aspect of power quality i.e. voltage drop. This paper investigates four MPPT algorithms; Perturbation & Observation(P&O) Improved P&O Incremental Conductance(Incond) Differential coefficient method simulated with irradiation temperature change and shadow conditions.

• International Journal of Internet, Broadcasting and Communication
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• v.9 no.1
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• pp.29-34
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• 2017

Over the past several decades, embedded system and flight control computer technologies have been evolved to meet the diverse needs of the mobile device market. Current embedded systems are at the heart of technologies that can take advantage of small-sized specialized hardware while still providing high-efficiency performance at low cost. One of these key technologies is multiple memory banks. For example, a dual memory bank can provide two times more memory bandwidth in the same memory space. This benefit take lower cost to provide the same bandwidth. However, there is still few software technologies to support the efficient use of multiple memory banks. In this study, we present a technique to efficiently exploit multiple memory banks by software support. Specifically, our technique use an interference graph to optimally allocate data to different memory banks by an optimizing compiler. As a result, the execution time can be improved upto 7% with the proposed technique.

• Smart Media Journal
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• v.7 no.1
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• pp.37-44
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• 2018

Utilizing sequence control and numerical computing, embedded devices are used in a variety of automated systems, including those at industrial sites, in accordance with their control program. Since embedded devices are used as a control system in corporate industrial complexes, nuclear power plants and public transport infrastructure nowadays, deliberate attacks on them can cause significant economic and social damages. Most attacks aimed at embedded devices are data-coded, code-modulated, and control-programmed. The control programs for industry-automated embedded devices are designed to represent circuit structures, unlike common programming languages, and most industrial automation control programs are designed with a graphical language, LAD, which is difficult to process static analysis. Because of these characteristics, the vulnerability analysis and security related studies for industry automation control programs have only progressed up to the formal verification, real-time monitoring levels. Furthermore, the static analysis of industrial automation control programs, which can detect vulnerabilities in advance and prepare for attacks, stays poorly researched. Therefore, this study suggests a method to present a discussion on an industry automation control program designed to represent the circuit structure to increase the efficiency of static analysis of embedded industrial automation programs. It also proposes a medium term translation technology exploiting LLVM IR to comprehensively analyze the industrial automation control programs of various manufacturers. By using LLVM IR, it is possible to perform integrated analysis on dynamic analysis. In this study, a prototype program that converts to a logical expression type of medium language was developed with regards to the S company's control program in order to verify our method.

• The Transactions of the Korean Institute of Power Electronics
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• v.3 no.4
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• pp.338-345
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• 1998

The mathematical interpretation of a practical sampler which is useful to obtain the small signal models for the peak and average current mode controls is proposed. Due to the difficulties in applying the Shannons sampling theorem to the analysis of sampling effects embedded in the current mode control, several different approaches have been reported. However, these approaches require the information of the inductor current in a discrete expression, which restricts the application of the reported method only to the peak current mode control. In this paper, the mathematical expressions of sampling effects on a current loop which can directly apply the Shannons sampling theorem are newly proposed, and applied to the modeling of the peak current mode control. By the newly derived models of a practial smapler, the models in a discrete time domain and a continuous time domain are obtained. It is expected that the derived models are useful for the control loop design of power supplies. The effectiveness of the derived models are verified through the simulation and experimental results.