• Journal of the Institute of Convergence Signal Processing
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• v.23 no.3
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• pp.115-122
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• 2022

With the outbreak of COVID-19 a few years ago, video conferencing and electronic document work have increased, and for this reason, the proportion of computer work among modern people's daily routines is increasing. However, as more and more people work on computers in the wrong posture for a long time, the number of patients with poor eyesight and text neck is increasing. Until recently, many studies have been published to correct posture, but most of them have limitations that users may experience discomfort because they have to correct posture by wearing equipment. A posture correction sensor algorithm is proposed to prevent access to the minimum distance between a computer monitor and a person using an ultrasonic sensor device. At this time, an algorithm for minimizing false alarms among warning alarms that sound at the minimum distance is also proposed. Because the ultrasonic sensor device is used, posture correction can be performed without attaching a device to the body, and the user can relieve discomfort. In addition, experimental results showed that accuracy can be improved by reducing false alarms by removing more than half of the noise generated during distance measurement.

• Proceedings of the Korean Information Science Society Conference
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• 2007.06c
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• pp.500-504
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• 2007

Sparrow(스패로우)는 C/C++로 작성된 프로그램의 메모리 누수와 버퍼오버런 오류를 자동으로 프로그램 실행전에 찾아주는 도구이다. Sparrow는 실제 현장에서 쓰이는 상용 프로그램의 분석에 유용하게 쓰일 수 있도록 제작되었다. 이를 위해 분석기 엔진은 수십만 라인 이상의 소프트웨어를 적절한 시간과 정확도로 분석하기 할 수 있도록 많은 기술이 적용되었다. 또한 사용자의 편의성을 위해 대상 프로그램의 소스 구조를 자동으로 파악하여 분석을 준비하고, 거짓일 가능성이 높은 알람을 미리 제거하며, 발생한 알람의 원인을 설명해 준다. Sparrow로 httpd-2.2.2를 비롯한 오픈 소프트웨어들을 분석한 결과 실제 오류들을 찾아낼 수 있었다.

• KIISE Transactions on Computing Practices
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• v.23 no.1
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• pp.1-12
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• 2017

Preventive maintenance is required for best performance of facilities in large scale industry. Ultimately, the efficiency of production is maximized by preventing the failure of facilities in advance. Typically, regular maintenance is conducted manually; however, it is hard to prevent repeated failures. Also, since measures to prevent failure depend on proactive problem-solving by the facility expert, they have limitations when the expert is absent or diagnosis error is made by an unskilled expert. Alarm system is used to aid manual facility diagnosis and early detection. However, it is not efficient in practice, since it is designed to simply collect information and is activated even with small problems. In this study, we designed and developed an automated preventive maintenance system based on expert's experience in detecting failure, determining the cause, and predicting future system failure. We also discussed the system structure designed to reuse the expert's knowledge and its applications.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.49 no.4
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• pp.34-40
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• 2012

In wireless communication system, fading is an unavoidable problem. Hence, errors in form of BER are introduced with the transmitted signal. It is necessary to recognize the behavior of these errors in different fading channels. To obtain the mathematical solution for the average bit error rate(BER) of coherent MPSK, some techniques are presented. In this paper, the impact of diversity is also analyzed over slow and flat Rician fading channel. In here, the value of modulation index, M is varied and the effects of its variation are also depicted. So, these performance curves with different diversity values and fading parameter are useful to design and evaluate the radio channel for faithful communication system.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• fall
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• pp.201-204
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• 2021

최근 전동 킥보드 사용량이 크게 늘었으나, 다른 이동수단 대비 낮은 안정성과 사용자들의 헬멧 착용에 대한 인식 부족으로 인해 사고의 위험성이 큰 상황이다. 이에 대하여 정부는 헬멧 착용을 강제하는 법률을 제정하였으나, 경찰력의 한계에 따른 단속 미비로 여전히 헬멧 착용율은 낮다. 본 연구는 YOLO v3 알고리즘을 통해 학습시킨 딥러닝 모델을 활용하여 도로 상황을 촬영한 동영상 내에서 헬멧 착용자와 미착용자를 구분하고 미착용자 탐지 시 알람을 제공하는 시스템을 제시한다. 기존 YOLO 알고리즘 및 신경망을 적용하되, 전동 킥보드 데이터를 새로 수집하고 클래스를 구분하여 학습시켰다. 소수의 탐지 및 분류 오류를 보정하기 위해, 히스토그램 간 유사도를 측정해 최종적으로 객체를 추적 및 확정하고, 객체에 대한 헬멧 착용 여부를 통계적으로 확인한다.

• Proceedings of the KAIS Fall Conference
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• 2012.05b
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• pp.812-816
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• 2012

본 논문은 산사태 감지 및 붕괴예측을 위한 현장에 USN(Ubiquitous Sensor Network)을 적용한 실시간 모니터링 시스템 모델을 개발하였다. 이 시스템의 성능을 검증하기 위해 USN기반의 상시모니터링시스템모델을 제작하고 실험적 평가를 수행하였다. 성능평가는 지표변위 센서모듈 동작특성 실험적 평가, USN은 Data 수집 전송 효율성 실험적 평가, 개발한 상시감시모니터링 프로그램 동작성능 실험적 평가 등을 수행하였다. 성능평가 결과 지표변위 측정센서모듈은 변위각도에 일치성을 확인하고, USN은 지표변위 센서모듈로부터 측정된 Data를 상시모니터링시스템에 오류 없이 전송되는지를 확인하였으며, 개발한 상시모니터링 프로그램 동작기능은 실시간 모니터링 그래프, 임계동작 알고리즘, 위험성 통보 문자서비스(SMS)기능, 알람서비스기능, 현장 감시카메라 등 동작기능의 우수성을 실험으로 증명하였다. 따라서 본 연구에서 개발된 산사태 감지 예측을 위한 USN기반 실시간 모니터링 시스템 모델은 산사태위험성노출 지역에 원격 실시간 모니터링 시스템으로 널리 사용될 것으로 사료된다.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2022.05a
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• pp.504-506
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• 2022

The existing rooftop solar power generation systems focus mainly on the development of a fixed system because of system error along with safety problem. Accordingly, it is intended to develop a rooftop mounted smart solar power generation system by adding a solar tracking system and a monitoring system to the existing fixed rooftop solar power generation technology. It plans to develop and commercialize 'Rooftop Mounted Smart Solar Power Generation System' by applying solar tracking system, safety diagnosis and response system, abnormal diagnosis and alarm system, and external device control and monitoring systems.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.552-555
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• 2010

In this paper, we propose a context-aware system using wireless multi sensor module to monitor the state for industrial factory environment. Wireless multi sensor module combines sensing values which are collected from each acceleration, pressure, temperature and gas sensors. Moreover, it delivers this data to server after being encoded by RS code. Thereafter, RS decoder decodes the values that are received from wireless multi sensor module and fixes errors which occur in wireless communication. Based on decoded data, context-aware algorithm sets critical range and compares it to the sensing values, if the sensing values are out of the range, an event occurs by the algorithm. At the same time, if there is another sensing value which is out of the range for standby time T seconds, the algorithm orders 3 steps-alarm to occur depending on each situation. Through this system, it becomes eventually possible to monitor machines' condition effectively. From the simulation, we confirm that this system is efficient to status monitoring of industrial automation equipment.

• Journal of the Korea Society for Simulation
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• v.25 no.4
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• pp.127-135
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• 2016

Even thought modernized marine navigation devices help navigators, marine accidents has been often occurred and ship collision is one of the main types of the accidents. Various studies on the assessment method of collision risk have been reported, and studies using fuzzy theory are remarkable for the reason that reflect linguistic and ambiguous criteria for real situations. In these studies, collision risks were assessed on the assumption that the current state of navigation ship would be maintained. However, navigators ignore or turn off frequent alarms caused by the devices predicting collision risk, because they think that they can avoid the collisions in the most of situations. This paper proposes a model of predicting ship collision risk considering the general patterns of collision avoidance, and the approach is based on fuzzy inference and discrete event system specification (DEVS) formalism.