• Journal of the Institute of Electronics Engineers of Korea CI
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• v.42 no.2 s.302
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• pp.1-10
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• 2005

The current implementation of TCP for the Internet is not efficient when used for Mobile Ad hoc Networks (MANENTs). This is because TCP assumes that all packet losses are caused by congestion, whereas transmission errors are a main reason for packet losses in wireless networks. To remedy this situation and increase performance, we propose an end-to-end method of using propagation delays and the differences between propagation delays to distinguish the causes for packet losses. The proposed method has two characteristics: Firstly, it is energy-efficient because this solution is only initiated when a packet loss is detected. Secondly, our approach considers only the one way propagation delay and is more accurate in determining causes for packet losses than existing methods which consider round trip time. Petri net models of the proposed TCP and of the standard TCP have been built and simulations have been performed on them. Our simulation results show that the proposed approach increases throughput and reduces propagation delay compared with standard TCP.

• The KIPS Transactions:PartB
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• v.12B no.5 s.101
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• pp.595-606
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• 2005

The scale of game development are rapidly increasing as the blockbuster games which cost $7\~20$ billion won, often appear on the markets. The game mechanics which is concentrated on technological elements of the game, necessarily requires the management of quality. In this paper, we propose a computer simulator for the quality evaluation of game mechanics which can analyze the quality accurately and economically in the design phase. The proposed simulator provides Petri net[7,8] and Smalltalk[9] for convenient modeling. The simulator gives the realistic evaluation like play test because it uses the realistic data of gameplay environment such as player action-pattern, game world map, and item DB but the previous evaluation methods can not consider the realistic gameplay environment and can only cover a limited scope of evaluation. To prove good performance of the proposed simulator, we have 80 simulations for the quality evaluation of the game mechanics of Dungeon & Dragon[13,14] in a given world map. The simulation results show that the proposed simulator can evaluate the faultlessness, optimization, and play balance of the game mechanics and gives better good performance than other evaluation methods.

• The Transactions of the Korea Information Processing Society
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• v.1 no.2
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• pp.202-214
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• 1994

A functional reduction method of Petri nets is proposed. The method is based on interpretation of relations and transitions with functions which map one series of a relation a another. In particular, we propose CF-join which combines two transitions to new one after reduction of the common places, CE-join which superpose two transitions to one after superposition of the common places, and EQ-join which reduces the common places, after the Petri nets were explained be a relational scheme. A reduced net can be obtained without changing the properties such as liveness and boundness.

• 제어로봇시스템학회:학술대회논문집
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• 1991.10b
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• pp.1811-1816
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• 1991

In this paper we present how the deviation bound, which is a synchronic variable, can be used for checking liveness in Petri nets. Also, the deviation bound will be applied to detect or avoid deadlock situations and to characterize concurrency against sequential behaviors in automated manufacturing systems. In the current stage, we restrict the applicable domain of these methods to the Petri net structure that can be synthesized by combining common transitions or common places or common paths of Live-and-Bounded circuits.

• Journal of Korean Society for Quality Management
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• v.31 no.3
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• pp.114-125
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• 2003

In this paper, we deal with the problem of modeling of agent-based robot manufacturing cell. Its role is becoming increasingly important in automated manufacturing systems. For Object Oriented & Queueing Petri Nets (OO&QPNs), an extended formalism for the combined quantitative and qualitative analysis of different systems is used for structure and performance analysis of mobile robotic cell. In the case study, the OO&QPN model of a mobile robotic cell is represented and analyzed, considering multi-class parts, non-preemptive priority and alternative routing. Finally, the comparison of performance values between Shortest Process Time (SPT) rule and First Come First Serve (FCFS) rule is suggested. In general, SPT rule is most suitable for parts that have shorter processing time than others.

• Journal of Korea Multimedia Society
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• v.17 no.11
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• pp.1296-1306
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• 2014

Recently there are many attempts that IT convergence has been studied together with very different sector like art and music. If it is possible to make a formal model with combination of engineering with strong creative sector like music, there will be some advantages to analyze its contents easily. In this study, the model has been provided to utilize music analysis and compose algorithm through the formal model research of Sonata. To this end, this study has been provided a formal model of Sonata with the Petri net model being widely used and verify the effectiveness of the proposed model on the case of Piano Sonata K. 332.

• The Transactions of the Korea Information Processing Society
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• v.7 no.5
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• pp.1426-1433
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• 2000

As distributed computing systems become popular, many modeling techniques and methods have been developed in specify the specification formally and verify the distributed/concurrent sytems. In spite of importance of communication in distributed object-oriented systems, specifying of communication method generally has not been emphasized in the design phase. One reason is due to the system designer misunderstanding, that is, a specification needs to be independent on the implementation. However, since defining communication pattern indistributed object-oriented systems is more serious than the required message passing method in the design phase. specifying the communication pattern is necessary instead of postponing until the implementation. In this paper, two formal specification techniques, temporal logic method and Petri nets method, for the communication in distributed systems are discussed. One is based on the temporal logic, which specifies the different patterns of primitive predicates. This method enable to define the underlying mechanism which can be interpreted as constraints. The Petri net method helps to specify the dynamic behavior of communicational patterns using the properties of Petri nets.

• 제어로봇시스템학회:학술대회논문집
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• 2000.10a
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• pp.66-66
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• 2000

In this parer, we introduce an algorithm to control flows of the traffic in multi-intersections. It is pointed out that the main problem in traffic control is how to resolve the congested situations for the particular time-durations and directions. The heavy load to a certain direction usually leads the intersection to congested situations, and the adjacent intersections are affected. We control and analyze the traffic flow of multi-intersections consisting of five intersections, in which four intersections are linked to the four directions of the central one. The entrance of vehicles of each direction is described using the concept of probability. We compare the performance of the pretimed signal controls to the traffic adaptive signal controller using a Petri Net simulation tool, Exspect.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.21 no.47
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• pp.193-209
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• 1998

The objective of this paper is to present a methodology for design of the FMS by using a new modeling tool which is called SE&TPN(Safe Extended & Timed Petri Net). A FMS, which consists of various machine groups, may produce machine parts in different physical dimensions and lot size. The approach involves the SE&TPN modeling by Petri-nets. The proposed algorithm can handle determining of firing count vector by incidence matrix and adjustment of conflict using the marking of SE&TPN. The SE&TPN is defined as nets that can have at most one token in one place and can have elements such as permissive arcs and inhibitor arcs in addition to elements. The SE&TPN with permissive arcs and inhibitor arcs are intuitively direct approach to increase the modeling power of the SE&TPN. Finally, this paper is to develop a modulation to optimize the system problems of FMS using SE&TPN which describes exactly features of Petri Nets.

• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1289-1296
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• 2019

Non-functional requirements plays a critical role in designing variety of applications domain ranges from safety-critical systems to simple gaming applications. Performance is one of the crucial non-functional requirement, especially in control and safety systems, that validates the design. System risk can be quantified as a product of probability of system failure and severity of its impact. In this paper, we devise a technique to do the performance analysis of safety critical and control systems and to estimate performance based risk factor. The technique elaborates Petri nets to estimate performability to ensure system dependability requirements. We illustrate the technique on a case study of Nuclear Power Plant system. The technique has been validated on 17 safety critical and control systems of Nuclear Power Plant.