• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.380-386
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• 2017

Fennovoima's nuclear power plant, Hanhikivi 1, $Pyh{\ddot{a}}joki$, Finland, is currently in design phase, and its construction is scheduled to begin in 2018 and electricity production in 2024. The objective of this paper is to produce a preliminary list of safety-significant external event combinations including preliminary probability estimates, to be used in the probabilistic risk assessment of Hanhikivi 1 plant. Starting from the list of relevant single events, the relevant event combinations are identified based on seasonal variation, preconditions related to different events, and dependencies (fundamental and cascade type) between events. Using this method yields 30 relevant event combinations of two events for the Hanhikivi site. The preliminary probability of each combination is evaluated, and event combinations with extremely low probability are excluded from further analysis. Event combinations of three or more events are identified by adding possible events to the remaining combinations of two events. Finally, 10 relevant combinations of two events and three relevant combinations of three events remain. The results shall be considered preliminary and will be updated after evaluating more detailed effects of different events on plant safety.

• Proceedings of the Korea Society for Simulation Conference
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• 1998.10a
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• pp.124-127
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• 1998

One of the eventual goals of VR research is to provide valuable experiences to the participants. In this work, we view that the content of experience is composed of a sequence of events, and develop algorithms authoring those events. Event authoring can be realized by controlling agents in VE in two different modes: (1) the autonomous mode, in which the agent exhibit autonomous behaviors based on the current world status and its own personality, and (2) the event mode, in which the behaviors generated form the autonomous mode is further controlled to meet the needs of the experiment. We define the event authoring language, so that the authors can design experiments by writing event-programs. Then the architecture of event execution manager is described, which is the heart of event-program execution. prove the effectiveness of our approach by showing results of several experiments.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1995.11a
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• pp.115-125
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• 1995

본 논문에서는 컴퓨터 시스템에서 침입 감지 시스템을 설계함에 있어서 사용될 수 있는 새로운 방법인 Event Sequence Tracking 방법을 제안하였다. Event Sequence Tracking 방법에서는 컴퓨터 시스템의 공격방법을 크게 두가지로 분류한다. 첫번째는 일련의 시스템 명령어를 이용한 공격방법이고 두번째는 침입자 자신이 만들었거나 다른 사람으로부터 얻은 프로그램을 이용하는 방법이다. 첫번째 공격방법에 대한 감지방법은 시스템을 공격할 때 사용한 일련의 시스템 명령어들을 감사 데이타를 분석하여 찾아내고 이 결과를 기존에 알려진 공격 시나리오들과 비교하여 침입자를 찾아내는 방식이다. 두번째 공격방법에 대한 감지 방법은 보안 관리자가 정해놓은, 시스템에서 일반 사용자가 할 수 없는 행위에 관한 보안 정책에 따라 Key-Event 데이타 베이스를 만들고 여기에 해당하는 event의 집합을 감사 데이타에서 찾아내는 방법이다. Event Sequence Tracking 방법은 Rule-based Penetration Identification 방법의 일종으로서 시스템의 공격방법을 분류하여 컴퓨터 시스템에의 침입을 효과적으로 감지할 수 있다는 것과 rule-base의 생성과 갱신을 함에 있어서 보다 간단하게 할 수 있다는 장점을 갖는다.

• Language and Information
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• v.7 no.2
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• pp.139-161
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• 2003

The progressive in English is taken to be an operator which takes a non-stative predicate and returns a predicate which denotes a process with a temporal frame around some definite time or event. When, it is combined with a predicate which has a culmination in the event, the sentence means that the culmination has not come yet. So the event denoted by the base predicate is not true at the current time. On the other hand, when it is combined with a predicate which has no culmination in the event, the event denoted by the base predicate is taken to be true. In this paper, this is explained by the semantics of the progressive based on the notion of contributiveness. I propose that a progressive sentence is verified by some subevents which are contributive to the current situation and the progress of the event beyond the threshold level of the event denoted by the base predicate. A sub-situation is contributive if the addition of it to the previous situation is more likely to lead to the whole situation than the previous situation.

• Journal of the Korea Society for Simulation
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• v.10 no.3
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• pp.1-14
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• 2001

A hybrid system is defined as a mixture of continuous systems and discrete event systems. This paper first proposes a framework for hybrid systems modeling, called Hybrid Discrete Event System Specification (HDEVS) formalism. It then presents a method for simulators interoperation in which a continuous system simulator and a discrete event simulator are executed together in a cooperative manner. The formalism can specify a hybrid system in a way that a continuos system and a discrete event system are separately modeled by their own specification formalisms with a support of well-defined interface. We call such interface an A/E converter for analog-to- event conversion and an E/A converter for event-to-analog conversion. Simulators interoperation is based on the concept of pre-simulation in which simulation time for a continuous simulator is advanced in accordance with a discrete event simulator.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2010.10a
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• pp.102-105
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• 2010

Traditional Pub/Sub(Publish/Subscribe) Systems search all subscriptions that match an incoming event by broker(i.e. it is not considering the accuracy of matching between an incoming event and subscriptions and only consider that an event either matches a subscription or not). However, subscriptions that match an event may have priority, therefore, we need priority Pub/Sub system. In this paper, we define what the accuracy means in order to prioritize among subscriptions and propose the Priority Retrieval Technique based on accuracy that able to search subscriptions. The Priority Retrieval Technique is based on IS-Lists. We can search the results ordered by accuracy.

• Journal of the Society of Naval Architects of Korea
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• v.47 no.2
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• pp.248-257
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• 2010

In this study, a discrete event and dynamic-based discrete time combined simulation modeling architecture, which can be used to calculate equations of motions among discrete events, is developed. This is composed of a command model, which is in charge of discrete event simulation, a numerical integration model, which finds motions by numerically integrating equations of motions, and an external force and control force model, which calculates the force and transmits it to the equations. Using this architecture, we can develop dynamic-based simulation by simply connecting and combining models, and handle simultaneously discrete event and discrete time simulation. To verify the efficiency of the architecture, it is applied to the submarine diving and surfacing simulation.

• Journal of the Korean Institute of Telematics and Electronics S
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• v.36S no.7
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• pp.124-133
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• 1999

In this paper, an event detection algorithm is proposed based on the statistics of subblock images. For an event of small size, we first divide each image into smaller subblocks and then for camera trembling, we use the statistics of three kinds of images such as the input image, reference image, and their difference image as features of the event. Simulation results show that the proposed algorithm is much more effective in event detection than the conventional cases based on only the difference image.

• Nuclear Engineering and Technology
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• v.49 no.6
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• pp.1165-1171
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• 2017

The traditional form of parallelism in Monte Carlo particle transport simulations, wherein each individual particle history is considered a unit of work, does not lend itself well to data-level parallelism. Event-based algorithms, which were originally used for simulations on vector processors, may offer a path toward better utilizing data-level parallelism in modern computer architectures. In this study, a simple model is developed for estimating the efficiency of the event-based particle transport algorithm under two sets of assumptions. Data collected from simulations of four reactor problems using OpenMC was then used in conjunction with the models to calculate the speedup due to vectorization as a function of the size of the particle bank and the vector width. When each event type is assumed to have constant execution time, the achievable speedup is directly related to the particle bank size. We observed that the bank size generally needs to be at least 20 times greater than vector size to achieve vector efficiency greater than 90%. When the execution times for events are allowed to vary, the vector speedup is also limited by differences in the execution time for events being carried out in a single event-iteration.

• Journal of Broadcast Engineering
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• v.8 no.4
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• pp.399-409
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• 2003

In this paper, we present an Event Reporting which is one of the major items of MPEG-21 and exemplify two digital data broadcasting use case scenarios, and according1y we propose the Event Reporting message structure for MPEG-21 broadcasting contents that is based on these use case scenarios. Every interaction with a Digital Item in the multimedia framework can be called an Event. The need to standardize Event Reporting within the Multimedia Framework arise from the need to monitor and communicate amongst Peers and Users the Events relating to Digital Items and/or the programs and devices that operate on them at any given time. However, there are a number of difficulties in providing an accurate report about an Event. Different observers of the Event may have vastly different perspectives. In this paper, we describe a structure and vision of the Event Reporting. Besides we show the activities on MPEG-21 Event Reporting standardization.