• Journal of Korean Society of Industrial and Systems Engineering
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• v.41 no.4
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• pp.189-195
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• 2018

With the advent of the digital age, production and distribution of web pages has been exploding. Internet users frequently need to extract specific information they want from these vast web pages. However, it takes lots of time and effort for users to find a specific information in many web pages. While search engines that are commonly used provide users with web pages containing the information they are looking for on the Internet, additional time and efforts are required to find the specific information among extensive search results. Therefore, it is necessary to develop algorithms that can automatically extract specific information in web pages. Every year, thousands of international conference are held all over the world. Each international conference has a website and provides general information for the conference such as the date of the event, the venue, greeting, the abstract submission deadline for a paper, the date of the registration, etc. It is not easy for researchers to catch the abstract submission deadline quickly because it is displayed in various formats from conference to conference and frequently updated. This study focuses on the issue of extracting abstract submission deadlines from International conference websites. In this study, we use three machine learning models such as SVM, decision trees, and artificial neural network to develop algorithms to extract an abstract submission deadline in an international conference website. Performances of the suggested algorithms are evaluated using 2,200 conference websites.

• Journal of KIISE:Computer Systems and Theory
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• v.27 no.3
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• pp.337-344
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• 2000

In this paper, we define a Process Algebra ACSMR(Algebra of Communicating Shared Multiple Resources) for system specification and verification using multiple resources. ACSMR extends a concept of multiple resources in ACSR that is a branch of formal methods based on process algebra. We'll show that two specification and verification examples. One is the specification of system behavior in multiprocessor using EDF(Earliest-Deadline-First) which is a scheduling algorithm of a real-time system. The other is the specification of describing timing analysis and resources restriction in a super scalar processor using multiple ports registers.

• KSII Transactions on Internet and Information Systems (TIIS)
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• v.8 no.12
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• pp.4451-4466
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• 2014

We present joint radio selection and relay scheme that delivers data from a source to a sink in heterogeneous stationary sensor networks consisting of various radio interfaces. The proposed scheme finds the optimal relay nodes and their corresponding radio interfaces that minimize energy consumption throughout the network while satisfying the end-to-end packet deadline requirement. We formulate the problem of routing through radio interface selection into binary integer programs, and obtain the optimal solution by solving with an optimization solver. We examine a trade-off relationship between energy consumption and packet delay based on network level simulations. We show that given the end-to-end deadline requirement, our routing algorithm finds the most energy-efficient routing path and radio interface across mesh hops. We demonstrate that the proposed routing scheme exploits the given packet delivery time to turn into network benefit of reducing energy consumption compared to routing based on single radio interface.

• Annual Conference of KIPS
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• 2002.11b
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• pp.1631-1634
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• 2002

멀티미디어 서버는 클라이언트가 요청한 멀티미디어 데이터 스트림을 효율적으로 제공하기 위해 사용된다. 현재, 정보통신 기술의 발달로 인해 멀티미디어 서버는 멀티미디어 정보를 온라인으로 서비스 할 수 있게 되었다. 하지만 네트워크 상에서 발생하는 Packet Delay 에 때문에 서버에서 사용자에게 연속적이고 엄격한 실시간 제약이 있는 비디오 전송과 같은 멀티미디어 서비스를 제공하는 것은 매우 힘들다. 따라서, 본 논문에서는 서버에서 필요한 Packet 를 먼저 전송하여 Packet Delay 를 줄이는 방법을 제안하였다. MPEG-4 에서 오브젝트의 AU(Access Unit)들의 디코딩 시간을 표시하는 DTS(Decoding Time Stamp)를 참조하여 생성된 Deadline threshold 를 기준으로 Deadline 이 가장 빠른 AU부터 전송하는 스케줄링 알고리즘을 이용하여 MPEC-4 미디어 오브젝트를 스트리밍한다.

• Proceedings of the Korean Information Science Society Conference
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• 2002.10c
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• pp.370-372
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• 2002

다중처리기 상에서 실시간 태스크 스케줄링에 대한 연구가 현재 많이 수행되고 있지만, 주로 Pfair(P-fairness)와 EDF(Earliest Deadline First) 알고리즘에 대한 연구이다. Pfair는 이론적인 연구에 초점을 두고 있으며, EDF는 처리기들을 효율적으로 이용하지 못하는 문제점을 가지고 있다. 본 논문에서는 다중처리기 상의 주기적인 실시간 태스크 집합을 대상으로, LLA(Least Laxity Algorithm) 알고리즘이 높은 스케줄링 가능성(schedulability)을 가짐을 먼저 보인다. 다음으로 기존 알고리즘들의 문제점을 보완하기 위해 EDF와 LLA를 결합한 ED/LL(Earliest Deadline/Least Laxity)이라는 알고리즘을 제시한다. ED/LL은 LLA보다 문맥교환 횟수는 적고 EDF보다 스케줄링 가능성이 높으며, 구현 오버헤드도 크지 않다.

• Proceedings of the KIEE Conference
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• 2003.11c
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• pp.797-801
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• 2003

In this paper, a real-time communication method using a PICNET-NP (Plant Instrumentation and Control Network for Nuclear Power plant) is proposed with an analysis of the control network requirements of DCS (Distributed Control System) in nuclear power plants. The method satisfies deadline in case of worst data traffics by considering aperiodic and periodic real-time data and others.

• Journal of Internet Computing and Services
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• v.5 no.1
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• pp.67-84
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• 2004

Real-time database systems (RTDBS) are database systems whose transactions are associated with timing constraints such as deadlines. Therefore transaction needs to be completed by a certain deadline. Besides meeting timing constraints, a RTDBS needs to observe data consistency constraints as well. That is to say, unlike a conventional database system, whose main objective is to provide fast average response time, RTDBS may be evaluated based on how often transactions miss their deadline, the average lateness or tardiness of late transactions, the cost incurred in transactions missing their deadlines. Therefore, in RTDBS, transactions should be scheduled according to their criticalness and tightness of their deadlines, even If this means sacrificing fairness and system throughput, And It always must guarantee preceding process of the transaction with the higher priority. In this paper, we propose an efficient real-time scheduling algorithm (Multi-level EFDF) that alleviates problems of the existing real-time scheduling algorithms, a real-time concurrency control algorithm(2PL-FT) for firm and soft real-time transactions. And we compare the proposed 2PL F[ with AVCC in terms of the restarting ratio and the deadline missing ratio of transactions. We show through experiments that our algorithms achieve good performance over the other existing methods proposed earlier.

• KIPS Transactions on Computer and Communication Systems
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• v.11 no.11
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• pp.381-394
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• 2022

Recently, due to the personalization and customization of data, Internet-based services have increased requirements for real-time processing, such as real-time AI inference and data analysis, which must be handled immediately according to the user's situation or requirement. Real-time tasks have a set deadline from the start of each task to the return of the results, and the guarantee of the deadline is directly linked to the quality of the services. However, traditional container systems are limited in operating real-time tasks because they do not provide the ability to allocate and manage deadlines for tasks executed in containers. In addition, tasks such as AI inference and data analysis basically utilize graphical processing units (GPU), which typically have performance impacts on each other because performance isolation is not provided between containers. And the resource usage of the node alone cannot determine the deadline guarantee rate of each container or whether to deploy a new real-time container. In this paper, we propose a monitoring technique for tracking and managing the execution status of deadlines and real-time GPU tasks in containers to support real-time processing of GPU tasks running on containers, and a node list management technique for container placement on appropriate nodes to ensure deadlines. Furthermore, we demonstrate from experiments that the proposed technique has a very small impact on the system.

• Journal of the Korea Computer Industry Society
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• v.4 no.12
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• pp.1053-1068
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• 2003

In this paper, we propose a new scheduling method without timing covert channel of real-time transaction for secure database systems that implement mandatory access control. Our scheduling method use the wait queue based on security level to remove timing covert channel. And it use priority queue that consider transaction type, deadline, and weight. Therefore, the proposed scheduling method prevents timing covert channel because it is kept noninterference between transactions with different security level, and maximizes the sum of the weight of transactions that satisfy its deadline. The simulation results, is a comparison of traditional methods, show that our scheduling method is improved to 30%.

• The KIPS Transactions:PartA
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• v.18A no.4
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• pp.143-150
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• 2011

This paper presents an EDF based scheduling algorithm for scheduling imprecise computation model where each task consists of mandatory part and optional part. Imprecise computation is useful to manage overload condition. In overload situation, some optional parts should be removed. The proposed DOP algorithm removes optional parts of earlier deadline tasks to enhance flexibly for newly arriving tasks. A simulation result shows that DOP has better performance than other algorithms.