• Journal of Korean Society of Transportation
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• v.12 no.3
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• pp.49-64
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• 1994

The development of a mathematical modular framework based on Petri Network theory to model a traffic network is the subject of this paper. Traffic intersections are the primitive elements of a transportation network and are characterized as event driven and asynchronous systems. Petri network have been utilized to model these discrete event systems; further analysis of their structure can reveal information relevant to the concurrency, parallelism, synchronization, and deadlock avoidance issuse. The Petri-net based model of a generic traffic junction is presented. These modular networks are effective in synchronizing their components and can be used for modeling purposes of an asynchronous large scale transportation system. The derived model is suitable for simulations on a multiprocessor computer since its program execution safety is secured. The software pseudocode for simulating a transportation network model on a multiprocessor system is presented.

• IEMEK Journal of Embedded Systems and Applications
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• v.14 no.2
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• pp.87-96
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• 2019

Low power issue is one of the most critical problems in the Internet of Things (IoT), which are powered by battery. To solve this problem, various approaches have been presented so far. In this paper, we propose a method to reduce the power consumption by reducing the numbers of accesses into the flash memory consuming a large amount of power for on-chip software execution. Our approach is based on using cooperative logging structure to distribute the sampling overhead in single sensor node to adjacent nodes in case of rare-event applications. The proposed algorithm to identify event occurrence is newly introduced with negative feedback method by observing difference between past data and recent data coming from the sensor. When an event with need of flash access is determined, the proposed approach only allows access to write the sampled data in flash memory. The proposed event detection algorithm (EDA) result in 30% reduction of power consumption compared to the conventional flash write scheme for all cases of event. The sampled data from the sensor is first traced into the random access memory (RAM), and write access to the flash memory is delayed until the page buffer of the on-chip flash memory controller in the micro controller unit (MCU) is full of the numbers of the traced data, thereby reducing the frequency of accessing flash memory. This technique additionally reduces power consumption by 40% compared to flash-write all data. By sharing the sampling information via LoRa channel, the overhead in sampling data is distributed, to reduce the sampling load on each node, so that the 66% reduction of total power consumption is achieved in several IoT edge nodes by removing the sampling operation of duplicated data.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.49 no.1
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• pp.33-40
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• 2000

In this paper, an integrated method for the path planning and motion control of wheeled mobile robots using a hybrid system model and control is presented. The hybrid model including the continuous dynamics and discrete dynamics with the continuous and discrete state vector is derived for a two wheel driven mobile robot. The architecture of the hybrid control system for real time path planning and following is designed which has the 3-layered hierarchical structure : the discrete event system using the digital automata as the higher process, the continuous state system for the wheel velocity controls as the lower process, and the interface system as the interaction process between the continuous system as the low level and the discrete event system as the high level. The reference motion commands for autonomous navigation are generated by the abstracted motion in the discrete event system. The motion control tasks including the feasible path planning and autonomous motion control with various initial conditions are investigated as the applications by the simulation studies.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.9
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• pp.135-140
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• 2015

Web-services employ XML that is the well-formed structure as a de-facto standard to represent data. SOAP or REST is one of the representative web-services using XML based massage passing systems. The XML parser can be divided into event driven and DOM tree. A streaming parser as an event driven is widely used for high-speed parsing. Since the streaming parser processes XML documents in sequence, they have any limitation to improve system performance. In order to improve speed of streaming XML parser, we present multibyte based streaming XML hardware parser using the element analyzer instead of the state machine. Compared to other parsers, the proposed MStreXHP can achieve about 2.72 times improvement in the number of clock cycles to be consumed in comparison of characters and sustain about 7.8Gbps throughput. Therefore, our MStreXHP is desirable for the streaming XML hardware parser on high-performance systems.

• International Journal of High-Rise Buildings
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• v.2 no.2
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• pp.131-139
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• 2013

The field of structural fire engineering has evolved within the construction industry, driven largely by the acceptance of performance-based or goal-based design. This evolution has brought two disciplines very close together - that of structural engineering and fire engineering. This paper presents an overview of structural systems that are frequently adopted in tall building design; typical beams and columns, concrete filled steel tube columns and long span beams with web openings. It is shown that these structural members require a structural analysis in relation to their temperature evolution and failure modes to determine adequate thermal protection for a given fire resistance period. When this is accounted for, a more explicit understanding of the behaviour of the structure and significant cost savings can be achieved. This paper demonstrates the importance of structural fire assessments in the context of tall building design. It is shown that structural engineers are more than capable of assessing structural capacity in the event of fire using published methodologies. Rather than assumed performance, this approach can result in a safe and quantified design in the event of a fire.

• 시스템엔지니어링워크숍
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• s.4
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• pp.151-154
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• 2004

This paper presents the general system theory and its applications to the safety analysis method that is a recent trend over the traditional event-driven model. This new model is known as STAMP(Systems Theory Accident Modeling and Process)proposed by Nancy G. Leveson in MIT. The new model has benefits of systemic approaches concerning the system safety as a whole including the context it is in, its stimulants and outcomes, and its parts as well as the relationships among them in a holistic manner. The method consists of a hierarchical control structure, a process model, and the safety constraints governing the control. This paper demonstrates an example the contrasts the differences between the approaches of STAMP and the traditional safety models.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.12
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• pp.2061-2071
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• 2003

The macro-parametric approach, which is a method of CAD model exchange, has recently been proposed. CAD models can be exchanged in the form of a macro file, which is a sequence of modeling commands. As an event-driven commands set, the standard macro file can transfer design intents such as parameters, features and constraints. Moreover it is suitable for the network environment because the standard macro commands are open, explicit, and the data size is small. This paper introduces the concept of the macro-parametric method and proposes its representation using XML technology. Representing the macro-parametric data using XML allows managing vast amount of dynamic contents, Web-enabled distributed applications, and inherent characteristic of structure and validation.

• Journal of Information Processing Systems
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• v.10 no.3
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• pp.412-428
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• 2014

Request oriented sensor networks have stricter requirements than conventional event-driven or periodic report models. Therefore, in this paper we propose a minimum energy data aggregation (MEDA), which meets the requirements for request oriented sensor networks by exploiting a low power real-time scheduler, on-demand time synchronization, variable response frame structure, and adaptive retransmission. In addition we introduce a test bed consisting of a number of MEDA prototypes, which support near real-time bidirectional sensor networks. The experimental results also demonstrate that the MEDA guarantees deterministic aggregation time, enables minimum energy operation, and provides a reliable data aggregation service.

• Journal of the Korean Society of Systems Engineering
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• v.1 no.1
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• pp.20-25
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• 2005

This paper presents the general system theory and its applications to the safety analysis method that is a recent trend over the traditional event-driven model. This new model is known as STAMP(Systems Theory Accident Modeling and Process) proposed by Nancy G. Leveson in MIT. The new model has benefits o f systemic approaches concerning the system safety as a whole including the context it is in, its stimulants and outcomes, and its parts as well as the relationships among them in a holistic manner. The method consists of a hierarchical control structure, a process model, and the safety constraints governing the control. This paper demonstrates an example that contrasts the differences between the approaches of STAMP and the traditional safety models.

• Language and Information
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• v.2 no.1
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• pp.157-176
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• 1998

This paper claims that beneficiary adjuncts are best analyzed as involving external predication in a version of grammatical framework called Head-driven Phrase Structure Grammar. This paper also claims that verbal catefories need to include the attribute INDEX among their semantic components in order to account for the external predication proposed in this paper. This paper distinguishes between recipient and beneficiary reles and assumes that the former is a semantic argument of a verb-type relation and that the latter is an adjunct which makes a semantic contribution as a modifier. This approach achives a unified analysis of modification phenomena of nominal and verbal categories and it can also accomodate Parson's(1990) idea that a verbal category denotes a set of events, not just an event.