• Convergence Security Journal
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• v.16 no.5
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• pp.41-48
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• 2016

In this paper we propose a new method of security visualization, VisFlow, using traffic flows to solve the problems of existing traffic flows based visualization techniques that were a loss of end-to-end semantics of communication, reflection problem by symmetrical address coordinates space, and intuitive loss problem in mass of traffic. VisFlow, a simple and effective security visualization interface, can do a real-time analysis and monitoring the situation in the managed network with visualizing a variety of network behavior not seen in the individual traffic data that can be shaped into patterns. This is a way to increase the intuitiveness and usability by identifying the role of nodes and by visualizing the highlighted or simplified information based on their importance in 2D/3D space. In addition, it monitor the network security situation as a way to increase the informational effectively using the asymmetrical connecting line based on IP addresses between pairs of nodes. Administrator can do a real-time analysis and monitoring the situation in the managed network using VisFlow, it makes to effectively investigate the massive traffic data and is easy to intuitively understand the entire network situation.

• Journal of KIISE:Computing Practices and Letters
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• v.9 no.6
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• pp.662-673
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• 2003

This paper proposed a workflow enactment model to provide process management functions for the next generation Internet service environment such as Web Service and Grid Computing. The existing enterprise workflow enactment models could not meet the scalability and reliability requirements for aforementioned environments. To satisfy these requirements, this study addressed on applying P2P model to the workflow enactment model. Mathematical description and proof were employed to show the recovery based on set theory and we also showed performance enhancement through simulations, which demonstrated a comprehensive result giving more than 100 times fast response time than the existing centralized model on the same resources.

• Journal of the Korea Society of Computer and Information
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• v.15 no.7
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• pp.1-10
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• 2010

The power of computational Grid resources can be utilized on users desktop by employing workflow managers. It also helps scientists to conveniently put together and run their own scientific workflows. Generally, stage-in, process and stage-out are serially executed and workflow systems help automate this process. However, as the data size is exponentially increasing and more and more scientific workflows require multiple processing steps to obtain the desired output, we argue that the data movement will possess high portion of overall running time. In this paper, we improved staging time and design a new scheduler where the system can execute concurrently as many jobs as possible. Our simulation study shows that 10% to 40% improvement in running time can be achieved through our approach.

• The Journal of the Korea Contents Association
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• v.14 no.10
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• pp.10-19
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• 2014

In recent, hospital information systems are widely used to electronically record, manage and share the data collected in hospitals. Such systems have contributed greatly to improving the work efficiency in modern hospitals, however, the collected data concerning the patients should be appropriately processed and reused to provide the healthcare service providers with decision supports. Especially, this paper proposes the patient flow monitoring system for the operations management of the outpatient department for patients with chronic diseases, and discusses the related issues. The proposed system visualizes the standard process model extracted from the patient history data and various performance measures, and this enables the managers to evaluate and enhance the operations of the outpatient clinic. In this paper, the patient flow monitoring system is applied to the rheumatology clinic, and the prototype system optimized for I-pad is illustrated.

• Journal of Internet Computing and Services
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• v.3 no.6
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• pp.43-51
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• 2002

In this paper, we study the new packet dropping scheme using an active queue management algorithm. Active queue management mechanisms differ from the traditional drop tail mechanism in that in a drop tail queue packets are dropped when the buffer overflows, while in active queue management mechanisms, packets may be dropped early before congestion occurs, However, it still incurs high packet loss ratio when the buffer size is not large enough, By detecting congestion and notifying only a randomly selected fraction of connection, RED causes to the global synchronization and fairness problem. And also, it is the biggest problem that the network traffic characteristics need to be known in order to find the optimum average queue length, We propose a new efficient packet dropping method based on the active queue management for congestion control. The proposed scheme uses the per-flow rate and fair share rate estimates. To this end, we present the estimation algorithm to compute the flow arrival rate and the link fair rate, We shows the proposed method improves the network performance because the traffic generated can not cause rapid fluctuations in queue lengths which result in packet loss

• Journal of KIISE:Software and Applications
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• v.26 no.11
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• pp.1288-1297
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• 1999

오늘날 많은 워크플로우 응용들은 마감 시간과 같은 시간 제약 조건들의 효율적인 관리를 요구하고 있다. 이러한 시간 제약성 워크플로우의 가장 중요한 목적들 중의 하나는 마감 시간을 만족하는 워크플로우 인스턴스의 수를 최대화하는 것이다. 시간 제약성 워크플로우 처리의 성능을 개선하기 위해서는 효과적인 액티비티들의 마감 시간 할당 방법이 요구된다. 이에 본 논문에서는 액티비티의 체재 시간과 워크플로우 제어 구조들의 특성을 고려하여 효과적인 마감 시간 할당 방법인 PST를 제안한다. PST는 기존의 방법들과 달리 워크플로우 제어 흐름을 분석하여 액티비티의 마감 시간을 할당하기 때문에 과부하에서도 높은 성능을 지원할 수 있다. 부가적으로 기존의 방법들과 성능 평가를 통해 본 논문에서 제안된 방법의 효용성을 검증한다.Abstract Nowadays, many workflow applications are requiring efficient time management such as deadline. With time-constrained workflows, one of the most important goals is to maximize the number of workflow instances that satisfy the deadline. In this regard, effective deadline assignment mechanisms should be developed to achieve high performance of time-constrained workflow processing. We propose in this paper our novel deadline assignment method called PST based on both an activity's sojourn time and the characteristics of workflow control structures. Because the method allocates the deadline to activities from analyzing the control flow of workflow, it can support good and stable workflow performance even under the high workload. In addition, we validate the usefulness of our proposed method through various experiments.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.6
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• pp.1047-1054
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• 2022

With the advent of SDN, a next-generation network technology that separates the hardware and software areas of network equipment and defines the network using open source-based software, it solves the problems of complexity and scalability of the existing network system. It is now possible to configure a custom network according to the requirements. However, it has a structural disadvantage that a load on the network may occur due to a lot of control communication occurring between the controller and the switch, and many studies on network load distribution to effectively solve this have been preceded. In particular, in previous studies of load balancing techniques related to flow tables, many studies were conducted without consideration of flow entries, and as the number of flows increased, the packet processing speed decreased and the load was increased. To this end, we propose a new network load balancing technique that monitors flows in real time and applies dynamic flow management techniques to control the number of flows to an appropriate level while maintaining high packet processing speed.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.199-201
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• 2000

워크플로우 시스템은 비즈니스 OS라고 불리어질 만큼 복잡하고 많은 기능을 수행하고 있는 커다란 시스템이다. 최근엔 시스템의 주요 컴포넌트들이 객체 단위로 설계되며 코바와 같은 미들웨어를 통해 통신을 하는 수행구조를 갖는다. 적용 분야에 따라서 수행을 위해 생성되어진 객체들이 수만 수백만개가 동시에 존재하기도 한다. 운용 서버에서는 운용자의 요구에 따라 이러한 객체들과 통신을 해야 한다. 그러기 위해서는 운용 서버 내에서 이러한 객체들에 대한 레퍼런스들을 유지, 관리를 해야 한다. 또한 빈번한 통신으로 인해서 각각의 컴포넌트간에 부하가 걸리는 것을 방지하거나 올바른 실행을 보장하기 위해서 메지시의 구조를 최대한 효율적으로 구성하고, 흐름을 최적화 할 필요가 절실하다. 본 논문에서는 그러한 객체들이 구성되어지는 시점부터 유지 관리되며 요구 발생시 처리되는 시점까지의 효율적인 운영을 위한 방안들을 추출하여 제안하고 구현하였다.

• Proceedings of the Korean Information Science Society Conference
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• 2004.04a
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• pp.781-783
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• 2004

최근 종단 호스트에서 나타나는 데이터 전송의 병목현상이 두드러지면서 종단 호스트에 관한 많은 연구가 진행되고 있다. 기존의 연구를 통해 종단 호스트의 병목현상의 원인으로 TCP의 비효율적인 버퍼관리가 제기되었다. 특히 임베디드 환경에서는 시스템 자원이 제한적일 수밖에 없기 때문에 TCP의 버퍼관리의 효율성이 매우 중요하다. 본 논문에서는 새로운 TCP 버퍼할당 기법인 RTBA(Rate-Based TCP Buffer Allocation) 기법을 제안하였다. RTBA는 플로우의 RTT(Round Trip Time), RTO(Retransmit Time Out), 패킷 손실율 둥을 고려한 TCP의 기대전송율을 기반으로 버퍼를 동적으로 할당함으로써 상대적으로 적은 버퍼를 사용하는 임베디드 환경에서도 다수의 TCP 플로우들이 높은 전송성능을 얻게 한다. 실험을 통해 제안한 RTBA 기법이 기존의 고정적인 버퍼할당 기법에 비해 우수한 성능을 보임을 확인할 수 있었다.

• Journal of Korea Multimedia Society
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• v.7 no.10
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• pp.1389-1399
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• 2004

Modern computer networks are growing wider, more complicated. Therefore, we have needed so much the function of the performance management to, by making this kind of the network performance best fitted, guarantee Quality of Service which the users require. Currently, Netflow, RMON and Packet Capture methods are used to analyze Traffic, the principal function of the performance management, but they are not the fundamental solution from the integrated point of view. In this paper, we suggest the integrated performance management architecture and, by means of it, design and implement the performance man-agement system so that we can manage the performance of multi-technology and multi-vender devices.