• International Journal of Internet, Broadcasting and Communication
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• 제12권4호
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• pp.93-101
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• 2020

Shipyards are potential environments for using IoT services, sensor networks, and delay tolerant networks. Simulations of those services and networks strongly rely on human mobility models. Results obtained with an unrealistic model may not reflect the true performance of applications, protocols, and algorithms in a shipyard. A lot of synthetic models for human movements have been studied but most of them are generic and focus on the daily movements of humans on city scales. Nevertheless, workers in shipyards have unique movement characteristics such as movement speed, pause time, and attractions places. For instance, workers usually move to some places, where they work, and rarely move to other places in the factory. Movement characteristics of workers not only depend on workers but also on tasks, which they do. For instance, workers, who paint ships, have similar movement speed and pause time. Hence, in this paper, human movements in shipyards are studied. We propose a new human mobility model called the human mobility mode in shipyards (MIS). In MIS, workers are classified into multiple types. Movement characteristics of a worker are similar to other workers in the same type. Based on the visiting probability, workers have some places, where they frequently visits, and some places, where they rarely visit. We analyze real mobility traces and studie to achieve human movement characteristics from real traces. The results show that MIS provides a well-match to the movement characteristic from real traces.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권2호
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• pp.193-202
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• 2012

In this paper, we propose a new approach for compact range sensor system for real-time robot applications. Instead of using off-the-shelf camera and projector, we devise a compact system with a CMOS image-sensor and a DMD (Digital Micro-mirror Device) that yields smaller dimension ($168{\times}50{\times}60mm$) and lighter weight (500g). We also realize one chip hard-wired processing of projection of structured-light and computing the range by exploiting correspondences between CMOS images-ensor and DMD. This application-specific chip processing is implemented on an FPGA in real-time. Our range acquisition system performs 30 times faster than the same implementation in software. We also devise an efficient methodology to identify a proper light intensity to enhance the quality of range sensor and minimize the decoding error. Our experimental results show that the total-error is reduced by 16% compared to the average case.

• JSTS:Journal of Semiconductor Technology and Science
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• 제12권2호
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• pp.150-161
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• 2012

Eye detection is widely used in applications, such as face recognition, driver behavior analysis, and human-computer interaction. However, it is difficult to achieve real-time performance with software-based eye detection in an embedded environment. In this paper, we propose a parallel hardware architecture for real-time eye detection. We use the AdaBoost algorithm with modified census transform(MCT) to detect eyes on a face image. We parallelize part of the algorithm to speed up processing. Several downscaled pyramid images of the eye candidate region are generated in parallel using the input face image. We can detect the left and the right eye simultaneously using these downscaled images. The sequential data processing bottleneck caused by repetitive operation is removed by employing a pipelined parallel architecture. The proposed architecture is designed using Verilog HDL and implemented on a Virtex-5 FPGA for prototyping and evaluation. The proposed system can detect eyes within 0.15 ms in a VGA image.

• 한국인터넷방송통신학회논문지
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• 제20권1호
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• pp.231-237
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• 2020

본 논문에서는 가정에서의 환경 모니터링을 기반으로 하여 홈 IoT 시스템을 구현하였다. 구현한 시스템에서는 각종 센서들로부터 데이터들을 실시간으로 수집하고 서버로 전송하였다. 이들 데이터들의 기반으로 홈의 디바이스들을 자동 또는 수동으로 제어하는 것을 구현하였다. MQTT 프로토콜을 사용하여 토픽에 따라 실시간으로 받아들이는 센서들의 데이터의 값과 그 변화를 볼 수 있었다. 브로커(Broker)를 통해 실시간으로 받아지는 각 토픽별 데이터를 토대로 자동으로 환경을 제어하는 시스템의 구현하고 시험을 통하여 동작을 확인하였다. 이런 시스템은 향후 실시간으로 데이터를 추적 및 모니터링이 필요한 헬스케어, 산업용 IoT, 화재 예방 등에 유용하게 응용될 것이라 기대된다.

• 방송공학회논문지
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• 제25권2호
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• pp.192-199
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• 2020

최근 딥러닝 모델을 기반으로 한 객체 추적 알고리즘의 활용도가 증가하고 있다. 영상에서의 다중 객체의 추적을 위한 시스템은 대표적으로 객체 검출 알고리즘과 객체 추적 알고리즘의 연쇄된 형태로 구성되어있다. 하지만 여러 모듈로 구성된 연쇄 형태의 시스템은 고성능 컴퓨팅 환경을 요구하며 실제 어플리케이션으로의 적용에 제한사항으로 존재한다. 본 논문에서는 위와 같은 객체 검출-추적의 연쇄 형태의 시스템에서 객체 검출 모듈의 연산 관련 프로세스를 조정하여 저성능 컴퓨팅 환경에서도 실시간 동작을 가능하게 하는 방법을 제안한다.

• 한국컴퓨터그래픽스학회논문지
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• 제7권1호
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• pp.27-35
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• 2001

3D 컴퓨터 그래픽에서 그림자는 매우 중요한 요소이다. 그림자가 없으면 물체와 물체간의 정확한 위치를 파악하기가 어렵기 때문이다. 즉, 물체가 다른 물체에 바로 붙어있는지 조금 떨어져 있는지를 알아내기가 곤란한 것이다. 이러한 그림자의 중요성에도 불구하고 현존하는 3D 가속 하드웨어들은 그림자의 생성을 전혀 지원하지 못하고 있다. 또한, 이것을 보완하기 위해 많은 그림자 생성 알고리즘들이 제시되었지만 모두 그 한계가 명확하였다. 많은 그림자 생성 기법 중 텍스춰 하드웨어를 이용한 그림자 지도 기법은 광원과 물체가 고정되어 있을 경우 매우 빠른 속도로 그림자를 생성시킬 수 있지만 광원이나 물체가 움직일 경우에는 속도가 느려지게 된다. 본 논문에서는 그림자 지도 기법에 영상기반 렌더링 기법을 적용하여 실시간으로 그림자를 생성하고자 하였다. 본 논문의 기법은 매우 많은 메모리를 필요로 하기 때문에 데이터를 적당히 샘플링하여 웨이블릿 기반 압축 기법으로 압축하였고, 그림자를 생성할 때는 가장 가까이 저장된 그림자들을 2차원 보간하였다.

• 대한임베디드공학회논문지
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• 제14권6호
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• pp.295-311
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• 2019

The smart product market is growing year by year and is being used in many areas. There are various ways of interacting with smart products and users by inputting voice recognition, touch and finger movements. It is most important to detect an accurate hand region as a whole step to recognize hand movement. In this paper, we propose a method to detect accurate hand region in real time in various environments. A conventional method of detecting a hand region includes a method using depth information of a multi-sensor camera, a method of detecting a hand through machine learning, and a method of detecting a hand region using a color model. Among these methods, a method using a multi-sensor camera or a method using a machine learning requires a large amount of calculation and a high-performance PC is essential. Many computations are not suitable for embedded systems, and high-end PCs increase or decrease the price of smart products. The algorithm proposed in this paper detects the hand region using the color model, corrects the problems of the existing hand detection algorithm, and detects the accurate hand region based on various experimental environments.

• Smart Structures and Systems
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• 제14권4호
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• pp.617-641
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• 2014

The energy constraint is still a common issue for the practical application of wireless sensors, since they are usually powered by batteries which limit their lifetime. In this paper, a practical compound energy efficiency strategy is proposed and realized in the implementation of a real time wireless sensor platform. The platform is intended for wireless structural monitoring applications and consists of three parts, wireless sensing unit, base station and data acquisition and configuration software running in a computer within the Matlab environment. The high energy efficiency of the wireless sensor platform is achieved by a proposed adaptive radio transmission power control algorithm, and some straightforward methods, including adopting low power ICs and high efficient power management circuits, low duty cycle radio polling and switching off radio between two adjacent data packets' transmission. The adaptive transmission power control algorithm is based on the statistical average of the path loss estimations using a moving average filter. The algorithm is implemented in the wireless node and relies on the received signal strength feedback piggybacked in the ACK packet from the base station node to estimate the path loss. Therefore, it does not need any control packet overheads. Several experiments are carried out to investigate the link quality of radio channels, validate and evaluate the proposed adaptive transmission power control algorithm, including static and dynamic experiments.

• The Journal of the Acoustical Society of Korea
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• 제16권3E호
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• pp.56-61
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• 1997

In this paper, we describe a real-time implementation of a multi-channel auido codec system that is based on the MPEG-1 audio algorithm. The major feature of this system is that it has a flexible multi-DSP system that can be adapted for various applications with using up to four TMS320C40 DSPs. The purpose of this paper is to present the problems of the system and is to describe the optimized methods to solve the problems in the view of hardware and software. Our audio codec is composed of an encoder an a decoder system and the bit rate of bitstream is up to 384 kbps. Fast input/output interfaces, DSP overloads, and inter-DSP communications methods with high speed are considered in multi-DSP H/W. Also, to run real-time in S/W, optimizing methods of algorithm are considered. After implementation of system, the subjective assessment method, and 'triple stimulus/hidden reference/double blind' that recommended by ITU-R TG10/3 is adopted for the quality of our system. All test items except one are awarded difference grades(diffgrade) better than 1-. Form the results, multi-channel audio system can be used for HDTV service.

• 한국통신학회논문지
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• 제27권1C호
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• pp.11-20
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• 2002

본 논문에서는 통신망을 통한 실시간 비디오 트래픽의 전송에 있어, 망 자원을 효율적으로 사용하고 사용자에게는 원하는 레벨의 QoS를 제공할 수 있는 새로운 예측기반 동적 자원할당 방법을 제안한다. 제안된 방법에서는 사전에 사용자로 부터의 트래픽 정보 없이, 실시간 예측과 제공되어지는 QoS 정도를 관측하여 각 비디오 소스에 차별적으로 자원을 할당한다. 최대 패킷 지연과 패킷 손실율에 대한 실시간 QoS 관측을 위하여 간단한 구조의 지연 패킷 카운터 갱신과정을 제시하였으며, 현재까지 제공되어진 QoS 정도가 낮은 비디오가 우선적으로 자원을 할당 받을 수 있는 방법을 제안하였다. 모의실험을 통하여 제안된 방법은 높은 망 자원 이용율을 달성하는 동시에 기존의 방법이 제공할 수 없었던 연결법 QoS를 매우 정확히 제공할 수 있음을 보였다.