• Journal of KIISE:Computing Practices and Letters
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• v.16 no.4
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• pp.477-481
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• 2010

In this paper, we try to classify behavior patterns of a person around a bed based on a wireless sensor network system. We define five behavioral patterns and three states of a person around a bed which is described by a state machine. We collected data sensed by motion detection and vibration sensors installed around a bed from which a feature vector was extracted. Based on feature vector corresponding to behavioral patterns and the state machine, we established a model for behavioral patterns. To validate the model, experiments on subjects were performed and the model was fixed. These experimental results revealed that behavior patterns of a person around a bed can be classified well.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.12 no.9
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• pp.1547-1553
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• 2008

This paper presents a method that generates various facial expressions of vector graphic character by using the simplified principle component vector. First, we analyze principle components to the nine facial expression(astonished, delighted, etc.) redefined based on Russell's internal emotion state. From this, we find principle component vector having the biggest effect on the character's facial feature and expression and generate the facial expression by using that. Also we create natural intermediate characters and expressions by interpolating weighting values to character's feature and expression. We can save memory space considerably, and create intermediate expressions with a small computation. Hence the performance of character generation system can be considerably improved in web, mobile service and game that real time control is required.

• Journal of the Korean Institute of Intelligent Systems
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• v.13 no.3
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• pp.266-274
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• 2003

This paper considers an incremental support vector learning for the abnormality detection problems. One of the most well-known support vector learning methods for abnormality detection is the so-called SVDD(support vector data description), which seeks the strategy of utilizing balls defined on the kernel feature space in order to distinguish a set of normal data from all other possible abnormal objects. The major concern of this paper is to modify the SVDD into the direction of utilizing the relation between the optimal solution and incrementally given training data. After a thorough review about the original SVDD method, this paper establishes an incremental method for finding the optimal solution based on certain observations on the Lagrange dual problems. The applicability of the presented incremental method is illustrated via a design example.

• Journal of Korea Multimedia Society
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• v.12 no.8
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• pp.1155-1163
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• 2009

This paper proposes an automatic facial expression generation system of vector graphic character using gaussian process model. Proposed method extracts the main feature vectors from twenty-six facial data of character redefined based on Russell's internal emotion state. Also by using new gaussian process model, SGPLVM, we find low-dimensional feature data from extracted high-dimensional feature vectors, and learn probability distribution function (PDF). All parameters of PDF are estimated by maximization the likelihood of learned expression data, and these are used to select wanted facial expressions on two-dimensional space in real time. As a result of simulation, we confirm that proposed facial expression generation tool is working in the small facial expression datasets and can generate various facial expressions without prior knowledge about relation between facial expression and emotion.

• Proceedings of the KIPE Conference
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• 2016.07a
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• pp.515-516
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• 2016

QZSI(Quasi Z-Source Inverter)를 이용한 유도전동기 제어 시스템은 암단락 상태를 제어에 이용할 수 있어서 추가 컨버터 없이도 단일 구조로 가변 배터리 전압을 일정하게 승압할 수 있다. 암단락을 이용한 승압은 직류단 전압제어가 보장되어야 하며 전압 제어기 성능이 인버터 출력 전류 제어에 상당한 영향을 미친다. 본 논문은 QZSI에서 직류 전압을 승압시키기 위한 암단락 시간을 효율적으로 제어하여 인덕터 전류 리플을 감소시키는 변형 공간벡터방식을 이용하여 유도 전동기를 제어하고 시뮬레이션과 실험을 통해 이를 검증한다.

• Proceedings of the KIPE Conference
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• 2015.11a
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• pp.181-182
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• 2015

QZSI(Quasi Z-Source Inverter)를 이용한 유도전동기 제어시스템은 암단락 상태를 제어에 이용할 수 있어서 추가 컨버터 없이도 단일 구조로 가변 배터리 전압을 일정하게 승압할 수있다. 암단락을 이용한 승압은 직류단 전압제어가 보장되어야 하며 전압 제어기 성능이 인버터 출력 전류 제어에 상당한 영향을 미친다. 본 논문은 QZSI에서 직류 전압을 승압시키기 위한 암단락 시간을 효율적으로 제어하기 위한 변형 공간벡터방식을 이용하여 유도 전동기를 제어하고 시뮬레이션과 실험을 통해 이를 검증한다.

• Proceedings of the KIPE Conference
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• 2019.07a
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• pp.180-182
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• 2019

본 논문에서는 옵셋 전압을 이용한 3레벨 인버터의 불연속 PWM 방법을 제안한다. 스위칭 상태에 따른 3레벨 인버터의 출력전압을 벡터공간에서 도시하여 전압 변조 지수에 따른 DC 레일 및 중성단 클램핑 가능 영역을 분석한다. 이를 바탕으로, 3상 전압 지령 크기를 입력으로 받아 중성단의 클램핑 가능 여부를 판별하고 원하는 지점으로 클램핑 시켜주는 옵셋 전압 생성부를 제안한다. 제안된 방법은 공간 벡터 전압 변조 방식에 비해 간단하며, 기존 2레벨 인버터의 불연속 PWM 방식을 기반으로 하므로 구현에 용이하다. 시뮬레이션 및 실험으로 이론의 타당성 및 효과를 검증하였다.

• Journal of the Institute of Convergence Signal Processing
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• v.1 no.1
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• pp.32-41
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• 2000

In this paper, we proposed a method which predict the verb by using the neural network in order to enhance communication rate in augmentative communication system for Korean language disorders. Each word is represented by an information vector according to syntax and semantics, and is positioned at the state space by being partitioned into various regions different from a dictionary-like lexicon. Conceptual similarity is realized through position in state space. When a symbol was pressed, we could find the word for the symbol at the position in the state space. In order to prevent verb prediction's redundancy according to input units, we predicted the verb after separating class using the neural network. In the result we can enhance $20\% communication rate in the restricted space

• Journal of Internet Computing and Services
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• v.6 no.1
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• pp.85-93
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• 2005

This paper describes how to distribute high multi-dimensional facial expression data of vast quantity over a suitable space and produce facial expression animations by selecting expressions while animator navigates this space in real-time. We have constructed facial spaces by using about 2400 facial expression frames on this paper. These facial spaces are created by calculating of the shortest distance between two random expressions. The distance between two points In the space of expression, which is manifold space, is described approximately as following; When the linear distance of them is shorter than a decided value, if the two expressions are adjacent after defining the expression state vector of facial status using distance matrix expressing distance between two markers, this will be considered as the shortest distance (manifold distance) of the two expressions. Once the distance of those adjacent expressions was decided, We have taken a Floyd algorithm connecting these adjacent distances to yield the shortest distance of the two expressions. We have used CCA(Curvilinear Component Analysis) technique to visualize multi-dimensional spaces, the form of expressing space, into two dimensions. While the animators navigate this two dimensional spaces, they produce a facial animation by using user interface in real-time.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.9 no.6
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• pp.41-48
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• 1995

In field oriented control of Induction motors, speed sensor is required, which reduces the sturdiness of drive system and together with the expenditure of hardware for faultless transmission and processing of sensor signals it causes considerable expenses. These expensive sensors can be replaced by speed sensorless concept. And for good control, the knowledge of the rotor flux component or the rotor resistance are needs. Thus, this paper is based on a Extended Kalman Filter (EKF) that estimates the state variables that are required for the control by only measuring the line voltages and currents of the machine. the rotor time constant and speed estimated by the EKF show satisfactory agreement with the real values, with the simulation approaches.