• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.747-752
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• 2004

Researches about scheduling of the distributed real-time systems have been proposed. However, they have some weak points, not scheduling both sporadic and periodic tasks and messages or being unable to guaranteeing the end-to-end constraints due to omitting precedence relations between sporadic tasks. So this paper proposes a new scheduling method for distributed real-time systems consisting of sporadic and periodic tasks with precedence relations and sporadic and periodic messages, guaranteeing end-to-end constraints. The proposed method is based on a binary search-based period assignment algorithm, an end-to-end laxity-based priority assignment algorithm, and three kinds of schedulability analysis, node, network, and end-to-end schedulability analysis. In addition, this paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system, shows that existing scheduling methods such as Rate Monotonic (RM) scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints, and proposes an end-to-end laxity-based priority assignment algorithm.

• Journal of Institute of Control, Robotics and Systems
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• v.11 no.2
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• pp.175-185
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• 2005

The scheduling methods of the distributed real-time systems have been proposed. However, they have some weak points. They did not schedule both sporadic and periodic tasks and messages at the same time or did not consider the end-to-end constraints such as precedence relations between sporadic tasks. This means that system scheduling must guarantee the constraints of practical systems and be applicable to them. This paper proposes a new scheduling method that can be applied to more practical model of distributed real-time systems. System model consists of sporadic and periodic tasks with precedence relations and sporadic and periodic messages and has end-to-end constraints. The proposed method is based on a binary search-based period assignment algorithm, an end-to-end laxity-based priority assignment algorithm, and three kinds of schedulability analysis, node, network, and end-to-end schedulability analysis. In addition, this paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system, shows that existing scheduling methods such as Rate Monotonic scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints, and proposes an end-to-end laxity-based priority assignment algorithm.

• Proceedings of the KIEE Conference
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• 2004.05a
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• pp.59-61
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• 2004

Researches about scheduling distributed real-time systems have some weak points, not scheduling both sporadic and periodic tasks and messages or being unable to guaranteeing the end-to-end constraints due to omitting precedence relations between sporadic tasks. This paper describes the application model of sporadic tasks with precedence constraints in a distributed real-time system. It is shown that existing scheduling methods such as Rate Monotonic scheduling are not proper to be applied to the system having sporadic tasks with precedence constraints. So this paper proposes an end-to-end laxity-based priority assignment algorithm which considers the practical laxity of a task and allocates a proper priority to a task.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.396-404
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• 2012

This paper proposes an analysis method to check the schedulability of a set of sporadic tasks under earliest deadline first (EDF) scheduler. The sporadic task model consists of subtasks with precedence constraints, arbitrary arrival times and deadlines. In order to determine the schedulability, we present an approach to find exact worst case response time (WCRT) of subtatsks. With the technique presented in this paper, we exploit the precedence relations between subtasks in an accurate way while taking advantage of the deadline of different subtasks. Another nice feature of our approach is that it avoids calculation time overhead by exploiting the concept of deadline busy period. Experimental results show that this consideration leads to a significant improvement compared with existing work.

• The Journal of the Korea Contents Association
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• v.7 no.1
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• pp.83-93
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• 2007

In this paper, we address a power-aware scheduling algorithm for a mixed real-time system which consists of periodic and sporadic tasks, each of which is characterized by its minimum period, worst-case execution requirement and deadline. We propose a dynamic voltage scaling algorithm called DVSMT(DVS for mixed tasks), which dynamically scales down the supplying voltage(and thus the frequency) using on-line distribution of the borrowed resources when jobs complete while still meeting their deadlines. With this scheme, we could reduce more energy consumption. As the proposed algorithm can be easily incorporated with RTOS(Real-Time Operating System), it is applicable for handhold devices and sensor network nodes that use a limited battery power. Simulation results show that DVSMT saves up 60% more than the existing algorithms both in the periodic-task and mixed-task systems.

• Journal of Korea Multimedia Society
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• v.20 no.3
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• pp.562-570
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• 2017

One shot tasks like a MERSC handling policy, a cinema poster, and so on are too small, diverse, and sporadic to make them as apps or web applications. They are usually shared as the form of notes attached in the field or messages in smart phones. In order to support inter-operability with internet web sites, QR/NFC tags are attached to them. What matters in the web technology is that HTML5 standard does not supply the accessability of smart phones' resources like a camera, an audio, magnetic sensors, and etc. In this paper, we propose a universal smart phone application for handling various one-shot tasks in the same UI/UX. One-shot tasks are described with HTML5 web documents, and the URL for the web documents are stored in QR/NFC tags. A smart phone scans a tag, and then the web document is retrieved and presented finally. QR tags can be delivered to other smart phones through messages or SNS. We solve the problem of HTML5 standard supplying a resource access library with javascrippts. We suggested the whole architecture and the internal structure of QR/NFC tags. We show that our scheme is applicable to make variable one-shot tasks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2015.05a
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• pp.728-731
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• 2015

Nowadays, the majority of the manufacturing plant equipment tend to be transformed with automation system than traditional manual equipment. Production manager to make the process decision-making, not accustomed to manage and take advantage of professional decision-making technique. So rather than using the system proposed, it is common to undergo sporadic measures through the external intermediary. In this paper, whether possible delivery to match the delivery through the issue and decision-making system of the data input to be generated in the manufacturing process, review the supply information of the material used in the process, a plurality of input / output device We have proposed an input module that utilizes the Android Application and ATmega2560. As a result, easily cope with the improvement and change of process information of the work efficiency of the production business of the manufacturing process, and reduced plant data missing tasks, and management improvement to the improvement of the delivery compliance and product satisfaction by improving productivity we try to contribute to.

• Journal of the Korean Society for information Management
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• v.36 no.2
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• pp.153-174
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• 2019

This study was conducted to find out basic facts on educational resources in Korea and see how educators have managed their tasks without educational resource archives. The research had the following steps: 1) finding out how the current state of primary and secondary education resources is managed and type of educational resources via Web search and literature review, 2) conducting a survey to determine archiving priorities according to the value of resources to the users, and 3) engaging in a discussion with experts on merits of establishing an educational resource archive system. Due to sporadic management and restricted use of educational resources produced in Korea, the primary and secondary education resources are not easily available to the public even though the public and private sectors produce significant amount of resources. The survey result on preferred educational resource types for archiving showed the following top three: 1) actual case studies conducted in the field, 2) curriculum related resources, and 3) various textbooks adopted. Considering the value of educational resources and the necessity of archiving agencies, the experts recommended to set up a national archiving system of educational resources. This study hopes to raise awareness of the need to set up educational resource archives as a start.