• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.295-297
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• 2003

실시간 운영체제는 여러 개의 독립적인 태스크가 동시에 실행될 수 있는 멀티태스킹 환경을 제공한다. 이러한 독립적인 태스크들 사이에 정보를 주고받기 위해서는 태스크들 사이의 통신이 필요하며 이러한 ITC(Inter-Task Communication)를 지원하는 방법에는 Global Variable과 Message 전송 두 가지 방법이 있다. Global Variable 은 Data Corruption 의 위험이 있기 때문에 보통의 실시간 운영체제에서는 Message 전송 방식을 주로 사용하는데 이러한 방식에는 메시지 큐, 메시지 메일박스, 메시지 포트 등이 있다. 본 논문에서는 태스크들 간에 또는 태스크와 ISR(Interrupt Service Routine)이 여러 개의 메시지를 서로 전달할 수 있는 메시지 큐에 대해서 설명하고 있다. 또한 태스크 또는 ISR 이 메시지 큐로부터 메시지를 주고받을 때 메모리의 동적 할당을 보다 효과적으로 처리함으로써 효율적인 메시지 큐 제어기법에 대해서 제시하고 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2003.10a
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• pp.280-282
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• 2003

많은 산업 분야에서 사용되는 실시간 시스템은 논리적 정확성뿐만 아니라 시간적 정확성을 요구한다. 그래서 실시간 시스템에서 동작하는 작업들은 항상 마감시간을 지키기 위해 작업에 대한 스케줄링이 매우 중요한 요소가 된다. 그리고 시스템의 신뢰도를 높이기 위해서는 고장 감내가 반드시 필요하다. 특히. 현대 기술의 발달로 일부 분야에서 사용되어 지던 실시간 시스템이 실시간 내장형 시스템 형태로 다양한 분야에 사용되어 진다. 내장형 시스템을 개발하는데 있어 자원의 절약 또한 하나의 중요한 요소이다. 따라서 본 논문에서는 실시간 시스템에서의 작업들이 마감 시간을 만족하며 고장 감내를 보장하는 시간 중복 기법과 백업 기법을 혼합하여 주기적으로 동작하는 작업들의 신뢰도와 자원의 효율 및 절약을 높이는 스케줄링 기법을 제안하고 실험한다.

• Journal of Intelligence and Information Systems
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• v.1 no.1
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• pp.61-72
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• 1995

Dynamic and explicit ordering of strategies is a key process in modeling knowledge-level problem-solving behavior. This paper addressed the important problem of howl to make the scheduler more knowledge-intensive in a way that facilitates the acquisition, integration, and maintenance of the scheduler control knowledge. The solution a, pp.oach described in this paper involved formulating the scheduler task as a heuristic classification problem, and then implementing it as a classification expert system. By doing this, the wide spectrum of known methods of acquiring, refining, and maintaining the knowledge of a classification expert system are a, pp.icable to the scheduler control knowledge. One important innovation of this research is that of recursive heuristic classification : this paper demonstrates that it is possible to formulate and solve a key subcomponent of heuristic classification as heuristic classification problem. Another key innovation is the creation of a method of dynamic heuristic classification : the classification alternatives that are selected among are dynamically generated in real-time and then evidence is gathered for and aginst these alternatives. In contrast, the normal model of heuristic classification is that of structured selection between a set of preenumerated fixed alternatives.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.7
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• pp.124-129
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• 2004

Recently, the demand for the optical cable is rapidly growing because the number of internee user increases and high speed internet data transmission is required. But the present optical cable winding systems has some serious problems such as pile-up and collapse of cable usually near the flange of the bobbin in the process of the cable winding. To reduce the pile-up collapse in a cable winding systems, a new guiding system is developed for a high-speed self-align cable winding. First of all, the winding mechanism was analyzed and synchronization logics for the motions of winding, traversing, and the guiding were created. A prototype cable winding systems was manufactured to validate the new guiding system and the suggested logic. Experiment results showed that the winding system with the developed guiding system outperformed the system without the guiding system in reducing pile-up and collapse in the high-speed winding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.135-138
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• 2005

Robotic devices have been widely used in many medical applications due to their accuracy and programming ability. One of the applications is a virtual reality medical simulator, which trains medical personnel in a computer generated environment. In this paper, we are going to present an application, an epidural anesthesia trainer. Because performing epidural injections is a delicate task, it demands a high level of skill and precision from the physician. This trainer uses a robotic device and computer controlled solenoid valve to recreate interaction forces between the needle and the various layers of tissues around the spinal cord. The robotic device is responsible for generation of interaction forces in real time and can be used to be haptic guidance that allows the user to follow a previous recorded expert procedure and feel the encountered forces.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.12 no.11
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• pp.5252-5268
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• 2018

To support a large-scale Hadoop cluster, Hadoop heartbeat messages are designed to deliver the significant messages, including task scheduling and completion messages, via piggybacking to reduce the number of messages received by the NameNode. Although Hadoop is designed and optimized for high-throughput computing via batch processing, the real-time processing of large amounts of data in Hadoop is increasingly important. This paper evaluates Hadoop's performance and costs when the heartbeat period is controlled to support latency sensitive applications. Through an empirical study based on Hadoop 2.0 (YARN) architecture, we improve Hadoop's I/O performance as well as application performance by up to 13 percent compared to the default configuration. We offer a guideline that predicts the performance, costs and limitations of the total system by controlling the heartbeat period using simple equations. We show that Hive performance can be improved by tuning Hadoop's heartbeat periods through extensive experiments.

• Journal of Sensor Science and Technology
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• v.30 no.1
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• pp.15-19
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• 2021

Image processing is one of the major techniques that are used for computer vision. Nowadays, researchers are using machine learning and deep learning for the aforementioned task. In recent years, digit recognition tasks, i.e., automatic meter recognition approach using electric or water meters, have been studied several times. However, two major issues arise when we talk about previous studies: first, the use of the deep learning technique, which includes a large number of parameters that increase the computational cost and consume more power; and second, recent studies are limited to the detection of digits and not storing or providing detected digits to a database or mobile applications. This paper proposes a system that can detect the digital number of meter readings using a lightweight deep neural network (DNN) for low power consumption and send those digits to an Android mobile application in real-time to store them and make life easy. The proposed lightweight DNN is computationally inexpensive and exhibits accuracy similar to those of conventional DNNs.

• International conference on construction engineering and project management
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• 2007.03a
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• pp.520-529
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• 2007

Apportioning responsibilities of concurrent delay to the owner and the contractor is a difficult task, due to the sophisticate nature both in the schedule and in the factors that cause the delay. This research attempts to develop a simplified yet systematic approach that can be used for a fair apportionment of concurrent delay. A concurrent delay is defined herein as when the contractor and the owner have both caused independent critical path delays during the same approximate time period. Incorporating the concepts of windows analysis and critical path method (CPM), the developed approach has three "windowing of delay" steps to quickly apportion the delay in each of these windows, and a fourth step to sum up those apportioned delays to obtain each party's final responsibilities. This developed approach is found to be simple and effective at this stage; it will be tested against real cases in the near future.

• International conference on construction engineering and project management
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• 2009.05a
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• pp.464-471
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• 2009

Robot and application of IT skill of construction industry are slow comparatively than another thing industry by the feature. This research proposes progress management and real time information gathering through construction automation and RFID focused on steel structure construction. Building for RTPM system, must consider various variables and surrounding situation in construction field and it is the most important and difficult matter that draw right requirement and grasp relation between this requirements to accomplish one suitable task considering these environment. Therefore, in this study analyzes requirement and target for RTPM system based on scenario that is easy to draw requirement and apply this to use case model. Presented method suggests that represent relation between goals and way that refines goal systematically from requirement of RTPM system. And it could express for visualization through the Way that attaches nonfunctional elements of system with system internal goal.

• Proceedings of the Korea Information Processing Society Conference
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• 2009.04a
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• pp.670-673
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• 2009

TinyOS는 현재 가장 널리 사용되는 센서 노드용 운영체제이지만, 태스크의 실시간성을 지원하지 않는다는 단점이 있다. 이에 TinyOS에 실시간성을 부여하기 위한 다양한 연구가 진행되었다. 그러나 이들 연구는 TinyOS의 사용자 태스크에 대한 실시간성만을 고려하여, TinyOS 플랫폼이 제공하는 태스크가 포함된 실제의 센서 노드 작업에 대해서는 실시간성을 만족시키지 못한다는 문제점이 있다. 따라서 본 논문에서는 TinyOS에서 센서 노드 작업의 실시간성을 지원하는 새로운 스케줄링 기법을 제안하고자 한다. 이를 위해 기존 연구의 스케줄링 기법을 센서 노드 작업에 적용했을 때 나타나는 작업 중첩 현상과 우선순위 조정 현상을 분석하고, 이를 효율적으로 해결하는 비선점형 EDF(Earliest Deadline First) 작업 스케줄링 기법을 구현하였다. 그리고 제안한 스케줄링 기법은 TinyOS의 이벤트 기반 비선점형 속성을 유지하여 제한된 하드웨어 자원을 가지는 센서 노드에 적합하다는 것을 확인하였다.