• Proceedings of the Korea Information Processing Society Conference
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• 2003.11a
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• pp.49-52
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• 2003

본 논문에서는 실시간 감시 시스템의 응용분야를 위한 백그라운드 모델링과 업데이트 그리고 오브젝트 추출 시스템을 설계 구현한다. 일반적인 감시 시스템은 백그라운드의 모델링(background modeling)과 오브젝트의 검출(object detection), 오브젝트의 추적(tracking)으로 구성된다. 실시간 감시시스템을 가능하게 하기 위해서는 작은 시간 복잡도(low time complexity)로 백그라운드와 오브젝트를 검출할 수 있어야 하고 실외환경(outdoor)의 노이즈(noise)를 반영할 수 있어야 한다. 기존에는 빠른 백그라운드 모델링을 위해 분산, 평균, 최빈값 등을 사용한 연구들이 있었다. 이러한 방법들은 빠른 수행 속도를 보장하지만 노이즈를 오브젝트로 검출하는 문제점이 있다. 또 다른 연구 분야인 메디안(median) 검출 방법은 실외환경에 존재하는 노이즈 반영에 적합한 반면, 정렬(sorting) 연산에 많은 시간이 소요된다. 본 논문은 윈도우(Window) 기반의 러닝 윈도우 리스트(Running Window List)를 이용하여 메디안 정렬 시간을 최소화하고 실시간으로 백그라운드 모델링, 오브젝트 검출, 백그라운드 업데이트를 할 수 있는 방법을 제안한다.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 2002.11a
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• pp.302-305
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• 2002

인터넷의 확장과 함께 더 나은 보안 도구가 요구되고 있다. 최근 몇 년간 많은 기업에서 보안 전문가를 위한 제품을 출시했다. 그러나 새로운 도구가 나올 때 마다 새로운 위협이 발생했다. 이와 함께 새로운 개념의 보안 시스템이 필요하게 되었다. 인터넷 위협관리 시스템은 실시간으로 보안 경보를 중앙서버에서 수집하고 분석하여 실시간 분석, 경보 및 대응을 하는 시스템이다. 인터넷 위협 관리 시스템은 보안 관리자에게 전체 시스템들 간에 무슨 일이 일어났는지를 한눈에 볼 수 있게 해준다. 결과적으로 보안제품과 시스템을 감시하는데 투자되는 시간이 그만큼 줄여준다.

• Journal of Advanced Marine Engineering and Technology
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• v.40 no.1
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• pp.39-44
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• 2016

Automated voltage regulators (AVRs) are used on ships and offshore to automatically adjust the voltage based on real-time output voltage readings of the generator engine. Analog-type AVR was previously more commonly used, but is slowly being replaced with digital-type AVR because of increased demands of response time. This study presents a new digital AVR system that contains appropriate features of the AVR with respect to offshore unstable load conditions and poor operating conditions. Furthermore, experiments of load and voltage change prove the excellence of stability and response of the proposed system compared to previous AVR systems. Additionally, an integrated control system for a monitoring the output voltage and field current was developed to easily set the gain value.

• Journal of the Korea Society of Computer and Information
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• v.24 no.11
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• pp.29-39
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• 2019

As mobile robot applications increase in real life, the need of low cost autonomous driving are gradually increasing. We propose a novel vision-based real-time lane detection and tracking system that supports autonomous driving of mobile robots in constrained tracks which are designed considering indoor driving conditions of mobile robots. Considering the processing of lanes with various shapes and the pre-adjustment of operation parameters, the system structure with multi-operation modes are designed. In parameter tuning mode, thresholds of the color filter is dynamically adjusted based on the geometric property of the lane thickness. And in the unstable input mode of curved tracks and the stable input mode of straight tracks, lane feature pixels are adaptively extracted based on the geometric and temporal characteristics of the lanes and the lane model is fitted using the least-squared method. The track centerline is calculated using lane models and the motion model is simplified and tracked by a linear Kalman filter. In the driving experiments, it was confirmed that even in low-performance robot configurations, real-time processing produces the accurate autonomous driving in the constrained track.

• Journal of Korea Multimedia Society
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• v.7 no.7
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• pp.886-895
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• 2004

In this paper, we propose the dynamic allocation scheme of the CPU bandwidth to efficiently integrate and schedule these tasks in the same system, where multimedia tasks and hard real-time tasks can coexist simultaneously. Hard real-time tasks are guaranteed based on worst case execution times, whereas multimedia tasks modeled as soft real-time tasks are served based on mean parameters. This paper describes a server-based allocation scheme for assigning the CPU resource to two types of tasks. Especially for MPEG video streams, we show how to dynamically control the fraction of the CPU bandwidth allocated to each multimedia task. The primary purpose of the proposed method is to minimize the mean tardiness of multimedia tasks while satisfying the timing constraints of hard real-time tasks present in the system. We showed through simulations that the tardiness experienced by multimedia tasks under the proposed allocation scheme is much smaller than that experienced by using other scheme.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.38B no.9
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• pp.728-735
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• 2013

In this paper, we present a method of transmitting ECG signals in real-time mobile environment to be possible to implement the ubiquitous healthcare system. Because of the excessive amount of data transmission of ECG signals, it is necessary to propose a limitation to the real-time transmission. We propose a real-time electrocardiographic monitoring system based on the proposal of unusual waveform detection algorithm which detects the R-wave distortions from the arrhythmia ECG signals having unusual waveform of about 10% on average. It is very effective in terms of time and cost for medical staffs to monitor and analyze ECG signals for a long period of time. Monitoring unusual waveform by gradually adjusting the threshold values of potential and kurtosis makes the amount of data transmitted decrease and significance level of waveform to be enhanced. The unusual waveform detection algorithm is implemented with ubiquitous environment inter-working device client. It is applicable to ubiquitous healthcare system capable of real-time monitoring the ECG signal. While ensuring the mobility, it allows for real-time continuous monitoring of ECG signals.

• KDI Journal of Economic Policy
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• v.35 no.2
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• pp.71-105
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• 2013

Now that fiscal soundness is increasingly important influenced by the euro area fiscal crisis, early budget execution has been under the spotlight as a tool for economy control, other than typical expansionary method, such as supplementary budget. Basically, early budget execution is a fiscal policy instrument that reponses to economic fluctuations through modifying the inter-temporal allocation of fiscal expenditure within budget, without affecting fiscal soundness. This study empirically examines how effective the intert-temporal reallocation of fiscal expenditure is in economy control. Using Korea's Consolidated Fiscal data, the size of inter-temporal reallocation of fiscal expenditure is defined as changes of fiscal expenditure for one year excluding seasonal factors and used to explain real economic growth rate, a dependent variable. The result shows that the macroeconomic effect of the inter-temporal reallocation turns out meaningful in general, though some policy time lag exists. Meanwhile, a simulation using macroeconomic model finds that overall effect on economic growth is not large because increase in fiscal expenditure allocation at a certain point of time is canceled by the opposite direction within the same fiscal year. However, the inter-temporal reallocation is found to reduce volatility of key macroeconomic variables so as to contribute to partially stabilizing macroeconomy. In particular, such effect of economic stabilization seems to be highly apparent at the time of financial crisis, but not very noticeable in normal economic cycle.

• Proceedings of the Korean Information Science Society Conference
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• 1998.10a
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• pp.98-100
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• 1998

실시간 시스템은 서버와 같은 공유자원들에 대해서 보다 높은 우선순위 활동의 최악 블록시간(worst case blocking time)을 결정해야한다. 현재까지 분산 시스템을 위한 여러 서버 모델들이 제안되었으며 이러한 서버모델들에 우선순위 규약을 적용하여 실시간성을 높이고 있다. 본 논문에서는 RT- Mach에서 실시간성을 향상시키기 위한 새로운 모델을 제시하여 우선순위 반전 문제를 해결하기 위해 동적 스레드 관리자(dynamic thread manager) 를 제안하였다. 기존의 여러 서버 모델들과 달리 서버마다 동적 스레드 관리자를 두어 작업자 그룹내에서 유혹 스레드(idle thread)와 바쁜스레드 (busy thread ) 판별하여 적절한 스레드를 선정, 조정하고 서버로부터의 요구에 대해 최상위 우선순위를 할당하여 서버간의 우선순위 반전을 중이고 실시간성을 향상시키고자 했다.

• Journal of Digital Contents Society
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• v.6 no.3
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• pp.189-193
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• 2005

The Korean University faced the rapid challenge of M&A. The Korean Government had a evaluation of all Universities and colleges. This paper investigated the transactional and real time properties of the University Evaluation Indexes and suggested these indexes to the BI(Business Intelligence) system contents.

• Journal of Korean Society of Transportation
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• v.25 no.5
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• pp.173-182
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• 2007

An innovative feature of this study is to propose a methodology for evaluating safety performance in real time based on vehicle trajectory data extracted from video images. The essence of evaluating safety performance is to capture unsafe car-following events between individual vehicles traveling surveillance area. The proposed methodology applied two indices including real-time safety index (RSI) based on the concept of safe stopping distance and time-to-collision (TTC) to the evaluation of safety performance. It is believed that outcomes would be greatly utilized in developing a new generation of video images processing (VIP) based traffic detection systems capable of producing safety performance measurements. Relevant technical challenges for such detection systems are also discussed.