• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.691-693
• /
• 2017

A novel structure of fast locking phase locked loop (PLL) with time difference detector and Lock status indicator (LSI) is proposed in this paper. Fast locking time is achieved using LSI. It has been simulated and proved by HSPICE in a CMOS $0.18{\mu}m$ 1.8V process.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2017.05a
• /
• pp.697-699
• /
• 2017

A novel structure of phase locked loop (PLL) which has small size with D Flip-Flop and sub charge pump has been proposed. The area of loop filter usually occupying the larger portion of the chip is minimized using a single small capacitor. It has been simulated and proved by HSPICE in a CMOS $0.18{\mu}m$ 1.8V process.

• Proceedings of the Korean Information Science Society Conference
• /
• 2004.04b
• /
• pp.376-378
• /
• 2004

최근 클라이언트/서버 모델이 웹 기반의 컴퓨팅 환경으로 변화함에 딸라 웹 서비스 모델로 발전해왔다. 웹 서비스는 인터넷을 기반으로 표준화된 기술을 사용하여 서비스간에 상호작용을 함으로써. 플랫폼과 구현 언어에 대한 의존성을 제거 할 수 있다. 따라서, 다양한 환경에서 웹 서비스들이 개발되거나 개발 중에 있다. 기업에서는 표준화된 상호작용을 사용하여 작은 단위의 웹 서비스를 큰 단위의 렘 서비스로 통합하여 사용과 개발이 용이한 비즈니스 서비스를 제공하기 위한 통할 방법의 필요성이 증가하고 있다. 웹 서비스의 위상은 통합을 위한 메타 모델의 기능과 웹 서비스의 다양한 구현 형태로 이루어져 있다. 본 논문에서는 서비스 지향 아키텍처 상에서 공급자 측면에서 제공되는 웹 서비스를 통합하기 위한 위상을 제시하고자 한다. 이를 위해서, 웹 서비스를 논리적으로 계층화하여 정의하고, 논리적 계층 모델을 기반으로 웹 서비스 메타 모델을 생성한다. 위상의 다양한 구성은 메타 모델을 기반으로 제시된다. 마지막으로 웹 서비스 통합에 대한 사례연구를 제시한다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2014.05a
• /
• pp.679-681
• /
• 2014

The performance of M-ary APSK modulation system due to phase noise are analyzed in this paper. The effects for phase noise in the higher order modulation are simulated by using constellation of the higher order modulation signals. the simulated results are verified by comparing with the analytic results for lower order PSK modulation signals. Based on the evaluation of simulation method, the phase noise effects for higher order APSK modulation signals are suggested in this paper.

• Journal of Internet Computing and Services
• /
• v.24 no.1
• /
• pp.27-37
• /
• 2023

In this paper, we define a new Lucas-Padoovan sequence using the Padovan sequence, and a new topological interconnection network is constructed using it. Coding nonnegative integers using subsequences of the Lucas-Padovan sequence, and using this to construct a new Lucas-Padovan cubes to deal with topological properties.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• fall
• /
• pp.193-196
• /
• 2021

홀로그램(Hologram)은 3차원 물체에서 나오는 빛의 정보를 제어하는 기술이다. 현재는 컴퓨터 생성 홀로그램(CGH)으로 생성한 디지털 홀로그램에 관한 연구, 특히 물체에서 나오는 빛의 정보를 최대한 기록하고 재현하여 디지털 홀로그램의 해상도를 향상 시키려는 연구가 활발히 진행되고 있다. 이에 본 논문에서는 고해상도 홀로그램 영상을 얻기 위해 딥러닝 기반 초해상도(Super Resolution) 네트워크를 훈련 및 최적화하여, 저해상도 위상 홀로그램 영상으로부터 높은 화질의 홀로그램 영상을 재현하는 고해상도 위상 홀로그램 영상을 생성하는 것을 목표로 한다. 이때 위상 홀로그램 영상의 특성을 이용한 순환 손실 함수(Circular loss function)를 새롭게 제안하며, 기존의 이미지 초해상도 신경망 모델을 학습시킬 때 자주 사용하는 L1 손실 함수와 비교했을 때 약 0.13dB 정도의 성능 향상이 있었다.

• Proceedings of the Korean Society of Broadcast Engineers Conference
• /
• 2022.06a
• /
• pp.1195-1198
• /
• 2022

홀로그램은 빛의 세기와 위상 정보를 모두 기록함으로써 3차원 영상 정보를 기록 및 재현할 수 있는 차세대 영상 시스템이다. 홀로그램은 부동 소수점의 복소 데이터로 실수, 허수 또는 진폭, 위상 신호로 분리되어 압축된다. 본 논문에서는 복소 홀로그램 영상의 표현방식에 따른 압축성능을 비교해보고, 진폭-위상 압축에 대해 압축 친화적인 복소 홀로그램 변환 방식을 제안한다. 이후, 각 표현방식의 압축에서 효율적인 비트량 할당 방법을 제시한다. 본 논문은 제안방식인 QS 진폭-위상 표현이 실수-허수 표현만큼 높은 압축성능을 갖는 것을 확인하였다.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.27 no.3A
• /
• pp.196-204
• /
• 2002

The Sinusoidal Transform Coding(STC) is a vocoding scheme based on a sinusoidal model of a speech signal. The low bit-rate speech coding based on sinusoidal model is a method that models and synthesizes speech with fundamental frequency and its harmonic elements, spectral envelope and phase in the frequency region. In this paper, we propose the 2.4kbps low-rate speech coding algorithm using the sinusoidal model of a speech signal. In the proposed coder, the pitch frequency is estimated by choosing the frequency that makes least mean squared error between synthetic speech with all spectrum peaks and speech synthesized with chosen frequency and its harmonics. The spectral envelope is estimated using SEEVOC(Spectral Envelope Estimation VOCoder) algorithm and the discrete all-pole model. The phase information is obtained using the time of pitch pulse occurrence, i.e., the onset time, as well as the phase of the vocal tract system. Experimental results show that the synthetic speech preserves both the formant and phase information of the original speech very well. The performance of the coder has been evaluated in terms of the MOS test based on informal listening tests, and it achieved over the MOS score of 3.1.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.9 no.3
• /
• pp.638-646
• /
• 2005

In recent wireless communications, direct conversion transceiver or If sampling SDR-based receivers have being designed as an alternative to conventional transceiver topologies. In direct conversion receiver a.chitectu.e, the 1.equency/phase offset between the RF input signal and the local oscillator signal is a major impairment factor even though the conventional AFC/APC compensates the service deterioration due to the offset. To rover the limited tracking range of the conventional method and effectively aid compensation scheme in terms of I/Q channel imbalances, the frequency/phase offset compensation in RF-front end signal stage is proposed in this paper. In RF-front end, the varying phase offset besides the fixed large frequency/phase offset are corrected by using early-late phase compensator. A more simple frequency and phase tacking function in digital signal processing stage of direct conversion receiver is effectively available by an ingenious frequency/phase offset tracking method in RF front-end stage.

• Journal of KIISE:Software and Applications
• /
• v.28 no.12
• /
• pp.875-884
• /
• 2001

Although the self organizing map (SOM) is widely utilized in such fields of data visualization and topology preserving mapping, since it should have the topology fixed before trained, it has some shortcomings that it is difficult to apply it to practical problems, and classification capability is quite low despite better clustering performance. To overcome these points this paper proposes the dynamic topology preserving self-organizing map(DTSOM) that dynamically splits the output nodes on the map and trains them, and attempts to improve the classification capability by combining multiple DTSOMs K-Winner method has been applied to combine DTSOMs which produces K outputs with winner node selection method. This produces even better performance than the conventional combining methods such as majority voting weighting, BKS Bayesian, Borda, Condorect and reliability sum. DTSOM remedies the shortcoming of determining the topology in advance, and the classification rate increases significantly by combing multiple maps trained with different features. Experimental results with handwritten digit recognition indicate that the proposed method works out to problems of conventional SOM effectively so to improve the classification rate to 98.1%.