• 정보처리학회논문지:소프트웨어 및 데이터공학
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• 제2권1호
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• pp.49-54
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• 2013

스마트폰 가속도 센서를 이용한 사용자 행위 인식은 동일한 행위를 수행하더라도 사용자마다 가속도 데이터 패턴이 서로 달라지는 사용자 의존성 문제를 가지고 있다. 그뿐만 아니라 스마트폰은 사용자의 어느 주머니나 손에도 놓일 수 있기 때문에 위치 의존성 문제도 지니고 있다. 본 논문에서는 특정 사용자나 특정 폰 위치에 대한 의존성이 적은 효과적인 행위 인식 방법을 제안한다. 제안한 방법을 기초로 안드로이드 스마트폰에서 동작하는 실시간 행위 인식 시스템을 구현하였다. 서로 다른 사용자와 서로 다른 폰 위치로부터 수집한 총 6642개의 샘플들을 이용한 실험을 통해, 본 논문에서 제안한 행위 인식 시스템의 성능을 분석하였다.

• 한국HCI학회:학술대회논문집
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• 한국HCI학회 2008년도 학술대회 1부
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• pp.499-503
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• 2008

In this paper, a novel human activity recognition method is proposed which utilizes independent components of activity shape information from image sequences and Hidden Markov Model (HMM) for recognition. Activities are represented by feature vectors from Independent Component Analysis (ICA) on video images, and based on these features; recognition is achieved by trained HMMs of activities. Our recognition performance has been compared to the conventional method where Principle Component Analysis (PCA) is typically used to derive activity shape features. Our results show that superior recognition is achieved with our proposed method especially for activities (e.g., skipping) that cannot be easily recognized by the conventional method.

• 한국지능정보시스템학회:학술대회논문집
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• 한국지능정보시스템학회 2007년도 추계학술대회
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• pp.439-443
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• 2007

Nowadays, activity recognition becomes a hot topic in context-aware computing. In activity recognition, machine learning techniques have been widely applied to learn the activity models from labeled activity samples. Most of the existing work uses only one learning method for activity learning and is focused on how to effectively utilize the labeled samples by refining the learning method. However, not much attention has been paid to the use of multiple classifiers for boosting the learning performance. In this paper, we use two methods to generate multiple classifiers. In the first method, the basic learning algorithms for each classifier are the same, while the training data is different (ASTD). In the second method, the basic learning algorithms for each classifier are different, while the training data is the same (ADTS). Experimental results indicate that ADTS can effectively improve activity recognition performance, while ASTD cannot achieve any improvement of the performance. We believe that the classifiers in ADTS are more diverse than those in ASTD.

• 한국멀티미디어학회논문지
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• 제15권8호
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• pp.1059-1066
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• 2012

오늘날 스마트폰의 발전으로 스마트폰 내장 센서를 통해 사용자의 개인 정보를 쉽게 파악 할 수 있고 원한다면 사용자의 위치를 실시간으로 알아낼 수 있다. 그리하여 센서를 통해 추출된 데이터를 통해 동작인식과 생활 패턴 인식에 관한 연구가 급증하고 있다. 본 논문에서는 기존의 동작 인식 연구에서 추출되는 데이터를 정형화하기 위해 동작 데이터를 모델링하였다. 본 논문의 일상 동작 모델링은 이론적 분석이다. 동작을 크게 두 가지로 분류시켜 가속도 센서만으로 인식 가능한 기본 동작을 물리적 동작으로 정의하고 그 외 목적과 대상, 장소를 포함하는 모든 동작을 논리적 동작으로 분류시켰다. 모델링 된 데이터를 기반으로 각 동작의 특성에 맞게 가시화 하는 방안을 제안하였다. 본 연구를 통해 인간의 일상생활을 동작별로 간편하게 표준화 할 수 있고 기존의 동작 인식 연구에서 추출되는 동작 데이터를 사용자의 요구에 따라 가시화 할 수 있다.

• 센서학회지
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• 제16권6호
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• pp.467-474
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• 2007

The real-time monitoring about the activity of the human provides useful information about the activity quantity and ability. The present study implemented a small-size and low-power acceleration monitoring system for convenient monitoring of activity quantity and recognition of emergent situations such as falling during daily life. For the wireless transmission of acceleration sensor signal, we developed a wireless transmission system based on a wireless sensor network. In addition, we developed a program for storing and monitoring wirelessly transmitted signals on PC in real-time. The performance of the implemented system was evaluated by assessing the output characteristic of the system according to the change of posture, and parameters and acontext recognition algorithm were developed in order to monitor activity volume during daily life and to recognize emergent situations such as falling. In particular, recognition error in the sudden change of acceleration was minimized by the application of a falling correction algorithm

• ETRI Journal
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• 제33권4호
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• pp.569-579
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• 2011

This paper presents a novel approach for human activity recognition (HAR) using the joint angles from a 3D model of a human body. Unlike conventional approaches in which the joint angles are computed from inverse kinematic analysis of the optical marker positions captured with multiple cameras, our approach utilizes the body joint angles estimated directly from time-series activity images acquired with a single stereo camera by co-registering a 3D body model to the stereo information. The estimated joint-angle features are then mapped into codewords to generate discrete symbols for a hidden Markov model (HMM) of each activity. With these symbols, each activity is trained through the HMM, and later, all the trained HMMs are used for activity recognition. The performance of our joint-angle-based HAR has been compared to that of a conventional binary and depth silhouette-based HAR, producing significantly better results in the recognition rate, especially for the activities that are not discernible with the conventional approaches.

• ETRI Journal
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• 제45권6호
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• pp.1079-1089
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• 2023

Stroke is one of the leading causes of long-term disability worldwide, placing huge burdens on individuals and society. Further, automatic human activity recognition is a challenging task that is vital to the future of healthcare and physical therapy. Using a baseline long short-term memory recurrent neural network, this study provides a novel dataset of stretching, upward stretching, flinging motions, hand-to-mouth movements, swiping gestures, and pouring motions for improved model training and testing of stroke-affected patients. A MATLAB application is used to output textual and audible prediction results. A wearable sensor with a triaxial accelerometer is used to collect preprocessed real-time data. The model is trained with features extracted from the actual patient to recognize new actions, and the recognition accuracy provided by multiple datasets is compared based on the same baseline model. When training and testing using the new dataset, the baseline model shows recognition accuracy that is 11% higher than the Activity Daily Living dataset, 22% higher than the Activity Recognition Single Chest-Mounted Accelerometer dataset, and 10% higher than another real-world dataset.

• KSII Transactions on Internet and Information Systems (TIIS)
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• 제11권2호
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• pp.1118-1133
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• 2017

Computer vision-based human activity recognition (HAR) has become very famous these days due to its applications in various fields such as smart home healthcare for elderly people. A video-based activity recognition system basically has many goals such as to react based on people's behavior that allows the systems to proactively assist them with their tasks. A novel approach is proposed in this work for depth video based human activity recognition using joint-based motion features of depth body shapes and Deep Belief Network (DBN). From depth video, different body parts of human activities are segmented first by means of a trained random forest. The motion features representing the magnitude and direction of each joint in next frame are extracted. Finally, the features are applied for training a DBN to be used for recognition later. The proposed HAR approach showed superior performance over conventional approaches on private and public datasets, indicating a prominent approach for practical applications in smartly controlled environments.

• Journal of Electrical Engineering and Technology
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• 제13권2호
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• pp.961-968
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• 2018

Recently, researches on automatic recognition of human activities have been actively carried out with the emergence of various intelligent systems. Since a large amount of visual data can be secured through Closed Circuit Television, it is required to recognize human behavior in a dynamic situation rather than a static situation. In this paper, we propose new intelligent human activity recognition model using the trajectory information extracted from the video sequence. The proposed model consists of three steps: segmentation and partitioning of trajectory step, feature extraction step, and behavioral learning step. First, the entire trajectory is fuzzy partitioned according to the motion characteristics, and then temporal features and spatial features are extracted. Using the extracted features, four pedestrian behaviors were modeled by decision tree learning algorithm and performance evaluation was performed. The experiments in this paper were conducted using Caviar data sets. Experimental results show that trajectory provides good activity recognition accuracy by extracting instantaneous property and distinctive regional property.

• 디지털융복합연구
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• 제9권2호
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• pp.101-110
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• 2011

본 연구는 블로그 이용경험이 있는 중국 네티즌들을 대상으로 블로그 요인과 블로거의 심리적 특성요인이 블로그 활동 윤리의식에 어떤 영향을 미치는 가를 알아보기 위해 이루어졌다. 연구결과 첫째 중국 네티즌의 블로그 이용형태는 자아추구적 이용, 사회참여업무적 이용, 타인교류적 이용 및 사적즐거움 이용형태로 나타났으며, 그 중 자아추구적 이용과 사회참여업무적 이용 형태가 블로그활동 윤리의식에 영향을 미치는 것으로 나타났다. 둘째, 중국 네티즌의 블로그 이용동기는 자아표현동기, 자아실현동기, 정보추구동기, 친구관계향상동기, 타인교류동기, 블로거 친구형성동기 및 은폐자아노출동기로 나타났으며, 정보추구동기,친구관계향상동기, 타인교류동기 및 은폐자아노출동기가 블로그 활동 윤리의식에 영향을 미치는 것으로 나타났다. 셋째, 네티즌 개인의 블로그 관여도와 사회참여 성향이 블로그 활동 윤리의식에 영향을 미치는 것으로 나타났다. 본 연구는 중국 네티즌들의 사회적 관계와 타인 교류동기 및 개인 심리적 특성이 블로그 활동 윤리의식에 영향을 미친다는 것을 실증적으로 확인했다는데 의의가 있다.