• 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.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.395-403
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• 2017

An efficient evaluation method for the probability of a tornado missile strike without using the Monte Carlo method is proposed in this paper. A major part of the proposed probability evaluation is based on numerical results computed using an in-house code, Tornado-borne missile analysis code, which enables us to evaluate the liftoff and flight behaviors of unconstrained objects on the ground driven by a tornado. Using the Tornado-borne missile analysis code, we can obtain a stochastic correlation between local wind speed and flight distance of each object, and this stochastic correlation is used to evaluate the conditional strike probability, $Q_V(r)$, of a missile located at position r, where the local wind speed is V. In contrast, the annual exceedance probability of local wind speed, which can be computed using a tornado hazard analysis code, is used to derive the probability density function, p(V). Then, we finally obtain the annual probability of tornado missile strike on a structure with the convolutional integration of product of $Q_V(r)$ and p(V) over V. The evaluation method is applied to a simple problem to qualitatively confirm the validity, and to quantitatively verify the results for two extreme cases in which an object is located just in the vicinity of or far away from the structure.

• Childhood Kidney Diseases
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• v.6 no.2
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• pp.251-258
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• 2002

We report the experiences of pump-driven continuous venovenous hemofiltration therapy in three children with acute renal failure. The all three patients required mechanical ventilation and needed the support of vasopressors. Renal replacement therapy was needed to meet the metabolic and fluid balance, but intermittent hemodialysis and peritoneal dialysis were not feasible because of hemodynamic instability and concurrent infection. We instituted pump-driven continuous venovenous hemofiltratlon (CVVH), and immediate improvement of pulmonary edema and successful removal of retained fluid were observed. Urea clearance also was satisfactory. During the filter running time, significant thromboembolic event or rapid drop of systemic blood pressure were absent. We concluded that the CVVH is an effective and safe method of renal support for critically ill pediatric patient.

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.89-100
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• 2011

The MAGLEV (Magnetically Levitated Vehicle) system, which is under commercialization as a new transportation system in Korea, is operated by means of unmanned automatic control system. Therefore the plan of train operation should be carefully established and validated in advance. In general, when making the train operation plan, the statistically predicted traffic data is used. However, traffic wave can occur when real train service is operated, and the demand-driven simulation technology is required to review train operation plans and service qualities considering traffic wave. This paper presents a method and model to simulate the MAGLEV's operation considering continuous demand changes. For this purpose, we employed the discrete event model which is suitable for modeling the behavior of railway passenger transportation, and modeled the system hierarchically using DEVS (Discrete Event System Specification) formalism. In addition, through the implementation and experiment using DEVSim++ simulation environment, we tested the feasibility of the proposed model and it is also verified that our demand-driven simulation technology could be used for the prior review of the train operation plans and strategies.

• Journal of Internet Computing and Services
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• v.12 no.4
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• pp.181-194
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• 2011

Server push which is technology of sending contents from servers to browsers in real time using long polling requests enables real time bidirectional communications between servers and browsers in HTTP environment. Recently, thanks to the rapid supply of mobile devices having ability of full browsing, server push is being applied to various applications. However, because servers providing services should offer distributed contents to a large number of users simultaneously in various user environments, they have a burden that offers contents quickly distinguishing much more concurrent users than before. The method of message exchange so far achieved in distributed server environment has difficulties in the performance of simultaneous user request process, the identification of users and the contents delivery. In this paper, We proposed message exchange architecture between servers for offering server push in the distributed server environment. The proposed architecture enables message exchange in the method of push between servers based on event driven architecture. In addition, the proposed architecture enables flexible identification of a event agent and event processing under the connected environment of a lot of users. In this paper, we designed and implemented the proposed architecture and compared performance with the previous way through a performance test. In addition, function is confirmed through the case realization. As a result of the performance test, the proposed architecture can lessen the use of server Thread and response time of users and increase simultaneous throughput.

• Journal of the Institute of Electronics Engineers of Korea TC
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• v.48 no.4
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• pp.61-68
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• 2011

Event-based service technology integrate service to detect events that occur in real time by analyzing the response. Is the core technology for real-time business and ubiquitous service environment construction. Is required event-based service technology on business processes in real-time business environment that providing rapid response to changing and custom service using a variety of information real-time monitoring and analysis in ubiquitous service environment. Last event-driven business processes can be used as a CEP(Complex Event Processing). The core of CEP technology, the event from multiple event sources analysis of events affecting and the way to handle action, is detect complex event to user. In previous studies, an event occurs that continue to perform without the need for partial operations. so many operations and spend a lot of memory is a problem. To solve these problems, event detection technique is proposed that large streams of data without processing any events, registered to configure a complex event occurs when all events in the application layer, complex event processing. The proposed method, first using a bitmap index to manage the event occurs. The complex events of the last event in response to define a trigger event. The occurrence of an event to display a bitmap index, a composite event occurrence of all event to configure the test through the point at which a trigger event occurs. Is proposed, If any event occurs to perform the operation. The proposed scheme perform operations when all event occurs without events having to perform each of the tests. As a result, avoid unnecessary operations and reducing the number of events to handle the increased efficiency of operations.

• The Journal of the Convergence on Culture Technology
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• v.8 no.1
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• pp.523-529
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• 2022

Art sponsorship contributed to the development of culture and art by supporting art activities to be financially stable. Various problems in the non-fungible tokens (NFTs) market, such as speculative transactions, are also expected to be improved through sound art sponsorship. This study proposes methods of implementing art sponsorship using NFTs and smart contracts. First, we propose a method of posting the acknowledgement of art sponsorship using NFT metadata. Second, we propose a method to remit sponsorship funds according to the project schedule using time-locked wallets. Third, we propose a method to remit sponsorship funds when major events of the project occur or requirements are met using Event-Driven Execution. The proposed methods can be used to share the fact about art sponsorship and safely fund it. However, many decisions about art projects must be made based on information generated outside the blockchain, which can lead to Oracle problems, so further research is needed.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1995.10a
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• pp.215-222
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• 1995

The objective of this paper is to develop a finite element structural analysis program using VB(Visual Basic) which has been recently getting popular as development tools of application program for Windows. VB provides several functions to develop an application program easily by supporting event-driven programming method and graphic object as control data type. This system is an integrated processor including preprocessor, solver and postprocessor. Automatic mesh generation is available at preprocess stage, and graphic presentation of deformation and stress is also represented at postprocess one.

• Proceedings of the Korea Society for Simulation Conference
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• 1999.10a
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• pp.24-29
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• 1999

Proposed in this paper is a modeling and simulation methodology for a virtual manufacturing environment. Based on DEVS formalism[Zeigler 76], the proposed model, so called GKDEVS, is designed to descript the geometrical knematic structure as well as event-driven and continuous state dynamics. In terms of abstract simulation algorithm[Zeigler 84], the simulation method of GKDEVS is proposed for combined discrete-continuous simulation. Using the GKDEVS, and FMS model consisting of a turing machine, a 3-axis machine and a RGV-mounted robot is constructed and simulated.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.21 no.9
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• pp.2415-2421
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• 1996

This paper describes implementation and performance evaluation of XTP(Xpress Transport Protocol) onthe Windows NT for multicasting in high-speed communication networks. We designed the protocol byan event-driven method and implemented it in form of network driver in a kernel for performace enhancement. Various applications program are used for its functional test and comparison with the TCP protocol.