• Journal of Power Electronics
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• v.10 no.4
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• pp.351-356
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• 2010

A new current-balancing multi-channel LED driver is proposed in this paper. The conventional LED driver system consists of three cascaded power conversion stages and its driver stage has the same number of expensive boost converters as those of the LED channels. On the other hand, the proposed LED driver system consists of two cascaded power stages and its driver stage requires only passive devices instead of expensive boost converters. Nevertheless, all of the currents through multi-channel LEDs can be well balanced. Therefore, it features a smaller system size, improved efficiency, and lower cost. To confirm the validity of the proposed driver, its operation and performance are verified on a prototype for a 46" LCD TV.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1575-1581
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• 2019

Due to the mismatched line impedance among distributed generation units (DGs) and uncontrolled harmonic current, the droop controller has a number of problems such as inaccurate reactive power sharing and voltage distortion at the point of common coupling (PCC). To solve these problems, this paper proposes a resistive-capacitive virtual impedance control method. The proposed control method modifies the DG output impedance at the fundamental and harmonic frequencies to compensate the mismatched line impedance among DGs and to regulate the harmonic current. Finally, reactive power sharing is accurately achieved, and the PCC voltage distortion is compensated. In addition, adaptively controlling the virtual impedance guarantees compensation performance in spite of load changes. The effectiveness of the proposed control method was verified by experimental results.

• ETRI Journal
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• v.43 no.6
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• pp.1049-1057
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• 2021

Automatic spacing in Korean is used to correct spacing units in a given input sentence. The demand for automatic spacing has been increasing owing to frequent incorrect spacing in recent media, such as the Internet and mobile networks. Therefore, herein, we propose a transformer encoder that reads a sentence bidirectionally and can be pretrained using an out-of-task corpus. Notably, our model exhibited the highest character accuracy (98.42%) among the existing automatic spacing models for Korean. We experimentally validated the effectiveness of bidirectional encoding and pretraining for automatic spacing in Korean. Moreover, we conclude that pretraining is more important than fine-tuning and data size.

• Journal of IKEEE
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• v.22 no.4
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• pp.1222-1225
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• 2018

This paper proposes an image detection algorithm to implement gesture. By using a camera sensor, the performance of the extracted image algorithm based on the gesture pattern was verified through experiments. In addition, through the experiments, we confirmed the proposed method's possibility of the implementation. For efficient image detection, we applied a segmentation technique based on image transition which divides into small units. To improve gesture recognition, the proposed method not only has high recognition rate and low false acceptance rate in real gesture environment, but also designed an algorithm that efficiently finds optimal thresholds that can be applied.

• Electronics and Telecommunications Trends
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• v.36 no.3
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• pp.87-96
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• 2021

Quantum computers will be a game-changer in various fields, such as cryptography and new materials. Quantum computer is quite different from the classical computer by using quantum-mechanical phenomena, such as superposition, entanglement, and interference. The main components of a quantum computer can be divided into quantum-algorithm, quantum-classical control interface, and quantum processor. Universal quantum computing, which can be applied in various industries, is expected to have more than millions of qubits with high enough gate accuracy. Currently, It uses general-purpose electronic equipment, which is placed in a rack, at room temperature to make electronic signals that control qubits. However, implementing a universal quantum computer with a low error rate requires a lot of qubits demands the change of the current control system to be an integrated and miniaturized system that can be operated at low temperatures. In this study, we explore the fundamental units of the control system, describe the problems and alternatives of the current control system, and discuss a future quantum control system.

• Electronics and Telecommunications Trends
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• v.38 no.3
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• pp.86-97
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• 2023

The outbreak of the novel coronavirus disease in 2020 caused a global semiconductor supply shortage and disruption in the production of devices such as iPhones owing to China's quarantine lockdown. Thus, Apple is diversifying its production bases from China to countries like India and Vietnam. The company is also accelerating semiconductor development to guarantee a stable supply, reduce design costs, and customize semiconductors with high quality and outstanding specifications for their products to outperform devices that use general-purpose semiconductors. Following the mobile application processor, Apple is releasing world-class semiconductors, such as the M1 and M2 chips that play the role of central processing units.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.47 no.6
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• pp.73-79
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• 2010

The number of electronic embedded software in vehicle system is ever increasing for years. As a result, the electronic control units have been growing dramatically, and it is required to mutual link between these units. Due to separate API each and every embedded platform, it is difficult to develop and integrate in automotive industry. The AUTOSAR project consists suppliers and manufacturers, and the partnership is a standardized platform to establish and develop an industry standard. On the previous works, we implemented the RTE generated module design based on AUTOSAR architecture. This paper specifically focuses on the testing of the development tool that generates RTE source code. The result satisfied a need for a RTE requirements and AUTOSAR methodology in a vehicle applications.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.43 no.4 s.310
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• pp.23-30
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• 2006

This paper presents design andd verification of a circuit that improves the control-operation problems of Stored Program Optical Computer (SPOC), which is an optical computer using $LiNbO_3$ optical switching element. Since the memory of SPOC takes the Delay Line Memory (DLM) architecture and instructions that are needless of operands should go though memory access stages, SPOC memory have problems; it takes immoderate access time and unnecessary operations are executed in Arithmetic Logical Unit (ALU) because desired operations can't be selectively executed. In this paper, improvement on circuit has been achieved by removing the memory access of instructions that are needless of operands by decoding instructions before locating operand. Unnecessary operations have been reduced by sending operands to some specific operational units, not to all the operational units in ALD. We show that total execution time of a program is minimized by using the Dual Instruction Register(DIR) architecture.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.39 no.7
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• pp.66-73
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• 2002

As floating-point operations become widely used in various applications such as computer graphics and high-definition DSP, the needs for fast division become increased. However, conventional floating-point dividers occupy a large hardware area, and bring bottle-becks to the entire floating-point operations. In this paper, a high-performance and small-area floating-point divider, which is suitable for embedded processors, is designed using he series expansion algorithm. The algorithm is selected to utilize two MAC(Multiply-ACcumulate) units for quadratic convergence to the correct quotient. The two MAC units for SIMD-DSP features are shared and the additional area for the division only is very small. The proposed divider supports all rounding modes defined by IEEE 754 standard, and error estimations are performed for appropriate precision.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.40 no.5
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• pp.266-279
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• 2003

In this paper, we propose machine printed character recognition methods which utilize the character type information and divide the character clusters. The characters are subdivided into a total of seven types, of which six types are for Hangul according to the grapheme combination fashions and one type for English characters, numerals, and symbols. According to the character type, we separate input character image into several recognition units and recognize them by using the direction angle feature. The recognition for each character type is completed by combining recognition units which are recognized by neural networks respectively For combining a total of seven character recognizers, we implemented seven methods such as switching method, integrating method, and their several variants. As experimental results, we obtained 98.2% recognition rate of simple switching method, 90.54% of integrating one, and between 97.35% and 98.65% of five variants.