• 한국시뮬레이션학회논문지
• /
• 제2권1호
• /
• pp.31-44
• /
• 1993

Zeigler's DEVS(Discrete Event Systems Specification) formalism supports formal specification of discrete event systems in a hierarchical , modular manner. Associated are hierarchical, distributed simulation algorithms, called abstract simulators, which interpret dynamics of DEVS models. This paper deals with performance evaluation of P-DEVSIM ++, a parallel simulation environment which implements the DEVS formalism and associated simulation algorithms in a parallel environment. Performance simulator has been developed and used to experiment models of parallel simulation executions in different conditions. The experimental result shows that simulation time depends on both the number of processors in the parallel system and the communication overheads among such processors.

• 한국시뮬레이션학회논문지
• /
• 제6권1호
• /
• pp.1-13
• /
• 1997

In this paper, we present a partitioning algorithm for distributed simulation of DEVS (Discrete Event System Specification) models. To preserve concurrency inherent in models, the proposed algorithm utilizes the structural information of models. Through benchmark simulation experiments, we show that the proposed algorithm can generate good partitions.

• 지질공학
• /
• 제18권2호
• /
• pp.191-196
• /
• 2008

이 연구는 집중호우시 산사태의 발생가능성과 발생시간을 사전에 예측하기 위한 노력의 일환으로 기존에 개발된 RTI 경보모델을 우리나라에 적용 분석한 사례이다. RTI(Rainfall Triggering Index)는 강우강도(I) 유효 누적강우량($R_t$)의 곱으로 정의되는 것으로서, 강우기간 동안 특정 시간(t)에서 산사태가 발생할 가능성을 평가하는데 사용된다. RTI의 상부임계값($RTI_{UC}$)과 하부임계값($RTI_{LC}$) 과거 산사태 발생시 강우자료 분석을 통해 각 지역별로 설정할 수 있으며, 강우강도가 상부임계값을 초과할 때 실제 산사태가 발생하는 것으로 이해할 수 있다. 이러한 분석은 궁극적으로 향후 집중호우가 내릴 경우 특정지역의 산사태 발생가능성은 물론 산사태 발생시기를 예상할 수 있으며, 이를 토대로 사전에 산사태 발생경보를 발령하는데 중요한 근거로 활용될 수 있다. 이와 같은 이론을 우리나라에 적용하기 위해 2006년 7월 13일부터 7월 19일까지 강원도 인제군 일대에 내린 강우자료와 산사태 발생과의 관계를 분석한 결과, 실제 산사태가 발생한 7월16일 오전 11시경을 기준으로 23시간, 11시간, 9시간 전에 강우강도가 RTI의 상부임계값을 초과하였다. 이를 토대로 이와 같은 세 차례에 걸친 산사태 경보의 발령이 필요하였음을 알 수 있었다.

• 한국멀티미디어학회논문지
• /
• 제20권2호
• /
• pp.254-260
• /
• 2017

Data packets from sensor nodes scattered over measuring fields are generally forwarding to the sink node, which may be connected to the wired networks, in a wireless sensor network. So many data packets are gathered near the sink node, resulting in significant data packet collisions and severe transmission latency. In an event detection application such as object tracking and military, bursty data is generated when an event occurs. So many data packet should be transmitted in a limited time to the sink node. In this paper, we present a delay efficient and bursty traffic friendly MAC protocol called DEBF-MAC protocol for wireless sensor networks. The DEBF-MAC uses a slot-reserved mechanism and sleep period control method to send multiple data packets efficiently in an operational cycle time. Our simulation results show that DEBF-MAC outperforms DW-MAC and SR-MAC in terms of energy consumption and transmission delay.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1998년도 The Korea Society for Simulation 98 춘계학술대회 논문집
• /
• pp.50-55
• /
• 1998

In this paper we use discrete simulation method to get the criteria of system evaluation required in the case of designing the complicated probabilistic event system having discrete probabilistic variables and to search the effective and reliable alternatives to satisfy the objective value of the given system through on-line, single run within the short time period. If we find the alternative we construct the algorithm which change values of decision variables and determining alternative by using the stopping algorithm which end the simulation in the steady state of system. In order to prevent the loss of data when we analyze the acquired design alternative in the steady state we provide the background of the estimation of the autoregressive model and mean and confidence interval for evaluating correctly the objective function obtained by the small amount of output data through the short time period simulation.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제12권8호
• /
• pp.3926-3945
• /
• 2018

In Jøsang's trust model, trust evaluation is obtained through operators, but there are problems with the mutuality and asymmetry of trust and the impact of event weight on trust evaluation. Trust evaluation is updated dynamically and continuously with time and the process of interactions, but it has not been reflected in Jøsang's model. Therefore, final trust evaluation is not accurate, and malicious fraud cannot be prevented effectively. This causes the success rate of interaction to be low. To solve these problems, a new dynamic trust model is proposed based on extended subjective logic (DTM-ESL). In DTM-ESL, the event weight and the mutuality of trust are fully considered, the original one-way trust relationship is extended to a two-way trust relationship, discounting and consensus operators are improved, and trust renewal is designed based on event weight. The viability and effectiveness of this new model are verified by simulation experiments.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2008년도 추계학술대회 논문집
• /
• pp.2116-2120
• /
• 2008

Recently, in the national railway industry there has been interested in the methodology of hazard analysis and risk assessment. The need of safety management system based on the technology of hazard analysis and risk assessment is being extended to identify in advance the weakness and threat factors causing the accident and cope with the accident actively. It is important to manage the risk of railway casualty accidents having a majority of railway accident. Especially, a hazard event of people struck takes the highest proportion of the railway casualty accidents. This paper describes the result of analysis for environment properties such as an age of casualty, time happened, day, month and weather conditions being concerned in the hazard event of people struck.

• International journal of advanced smart convergence
• /
• 제10권3호
• /
• pp.232-244
• /
• 2021

This study analyzed the changes in carbon monoxide, carbon dioxide, oxygen and visual distance by presence of sprinkler heads and their types in the event of a fire in an indoor gymnasium. Based on carbon monoxide and visual distance that affects human bodies enormously, first, if there is no sprinkler head, carbon monoxide will reach 0.4% within five seconds and visual distance rapidly shrank within five seconds. Seconds, in the event of standard sprinkler heads, carbon monoxide gradually increased from 30 seconds onwards and visual distance rapidly shrank after five seconds. Second, Third, if there are special sprinkler heads, carbon monoxide fluctuated after opening the head and visual distance became 5m or below from 15 seconds. Finally, in the event of early response sprinkler heads, carbon monoxide fluctuated up and down at 3 seconds due to falling water drops. Visual distance shrank up to 5m or below at 6 seconds. In the future, time for operation of each sprinkler head shall be analyzed.

• Spatial Information Research
• /
• 제22권3호
• /
• pp.1-8
• /
• 2014

최근 소셜 네트워크 서비스가 급격히 성장하면서, 소셜 네트워크 분석에 관련된 연구들도 많은 관심을 받고 있다. 특히 트위터는 사회적 이슈나 사건들에 대해 실시간으로 반응하기 때문에, 사회과학 분야나 정보검색 분야의 연구자들이 유용한 실험 데이터를 수집하는 데에 활용되고 있다. 그러나 정작 데이터를 수집하는 방법론에 관한 연구는 아직 미흡하다. 이에 본 논문에서는 위치 기반의 이벤트와 정치 사회적 이벤트 위주의 사용자의 성향을 고려한 트윗 수집 시스템을 제안한다. 우선 위치정보와 이벤트 관련 키워드를 포함하고 있는 트윗과 정치 사회적인 이벤트 검출에 필요한 ID들을 수집한 후, 사용자들의 성향을 분류할 ID 분석기를 설계했다. 또한 ID 분석기의 신뢰도 측정을 위해 상위 등급에 분류된 ID를 이용하여 트윗을 분석했다. 분석결과 1등급으로 분류된 ID는 88.8%의 신뢰도를 보였으며, 2등급으로 분류된 ID는 76.05%의 신뢰도를 보였다. 또한 ID 분석기는 77.5%의 신뢰도를 보였으며 소수의 ID를 사용함으로써 데이터의 수집시간을 줄였다.

• 대한전기학회논문지:전력기술부문A
• /
• 제48권6호
• /
• pp.760-772
• /
• 1999

The CAN is a serial communication protocol for distributed real-time control and automation systems. Data generated from field devices in the distributed control of power plant are classified into three categories: real-time event data, real-time control data, non-real-time data. These data share a CAN medium. If the traffic of the CAN protocol is not efficiently controlled, performance requirements of the power plant system could not be satisfied. This paper proposes a bandwidth allocation algorithm that can be applicable to the CAN protocol. The bandwidth allocation algorithm not only satisfies the performance requirements of the real-time systems in the power plant but also fully utilizes the bandwidth of CAN. The bandwidth allocation algorithm introduced in this paper is validated using the integrated discrete-event/continuous-time simulation model which comprises the CAN network and distributed control system of power plant.