• The Journal of Korean Institute of Communications and Information Sciences
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• v.30 no.4B
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• pp.170-177
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• 2005

Due to the redundant rebroadcast packets, network-wide broadcasting is a costly operation in wireless mobile ad hoc networks. To reduce this redundancy, most of previous approaches implicitly or explicitly require periodic refreshing of neighborhood information which continuously imposes additional broadcast overheads. In this paper, we propose a practical broadcast pruning scheme based on the local prediction of a remained coverage area. As the proposed scheme uses only information available in the on-going broadcast process, it can minimize the overheads prevalent in previous approaches.

• Journal of KIISE:Computing Practices and Letters
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• v.16 no.7
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• pp.759-767
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• 2010

RT-eCos 3.0 is a micro-sized embedded real-time kernel that has been developed based on the open source eCos 3.0 to support the basic task model of the well-known distributed real-time object model, TMO(Time-Triggered Message-triggered Object). In this paper, the design and implementation techniques of the RMMC(Real-time Multicast & Memory replication Channel) that is a standard distributed IPC model of the TMO is described based on the RT-eCos 3.0. And the support technique of the global time for using the same time in a distributed environment using the RMMC is also described. The developed global time based RMMC supports highly abstracted distributed IPC environment in a wide area distributed computing environment with the RT-eCos 3.0.

• Journal of the Institute of Electronics Engineers of Korea CI
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• v.41 no.3
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• pp.11-16
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• 2004

Recently, collaborative works are increased more and more over the distributed heterogeneous computing environments. The availability of high-speed wide-area networks has also enabled collaborative multimedia applications such as video conferencing, distributed interactive simulation and collaborative visualization. Distributed high performance computing and collaborative multimedia applications, it is extremely important to efficiently perform group communication over a heterogeneous network. Typical group communication patterns are broadcast and Multicast. Heuristic algorithms such as FEF, ECEF, look-ahead make up the message transmission tree for the broadcast and multicast over the distributed heterogeneous systems. But, there are some shortcomings because these select the optimal solution at each step, it may not be reached to the global optimum In this paper, we propose a new heuristic algerian that constructs tree for efficiently collective communication over the previous heterogeneous communication model which has heterogenity in both node and network. The previous heuristic algorithms my result in a locally optimal solution, so we present more reasonable and available criterion for choosing edge. Through the performance evaluation over the various communication cost, improved heuristic algorithm we proposed have less completion time than previous algorithms have, especially less time complexity than look-ahead approach.

• International Journal of Computer Science & Network Security
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• v.23 no.2
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• pp.203-209
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• 2023

The paper brings across data that is utilized in the Bring Your Own Device (BYOD) status collected between February and April of 2021 across Saudi Arabia. The data set was collected using questionnaires established through online mechanisms for the respondents. In the questionnaire, personal details included five questions while seven questions addressed the working model of personal mobile devices. Six questions addressed the awareness of employees bring your own device awareness for employees comprised seven questions and two questions addressed the benefits of business achievements. In the identification of suitable respondents for the research, two approaches were applied. The research demanded that the respondents be Saudi Arabian nationals and have attained 18 years. Snowball and purposive techniques were applied in the collection of information from a wide area of Saudi Arabia while employing social media approaches that include the use of WhatsApp and emails in the collection of data. The approach ensured the collection of data from 857 respondents used in the identification of the status as well as issues across the BYOD environment and accompanying solutions. The data was also used in the provision of awareness in the community through short-term courses, cyber security training and awareness programs. The results of the research are therefore applicable to the context of the Saudi Arabian country that is currently facing issues in dealing with the application of personal devices in the work environment.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.9
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• pp.1549-1559
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• 2010

Modern power system is operated and managed in closed network environment with treating a great variety of data, and requirement of real time power system data is more increasing. However, it is difficult for operators to fast evaluate the condition of power system using only isolation network system such as SCADA or EMS regarding unexpecting situations occurring. Recent technology achievement in areas of distributed computing, networking high speed communications and digital control as well as the availability of accurate GPS time source are rapidly becoming the enabling factors for the development of a new generation of real time power grid monitoring tools. In this paper, architecture of WAMAC which is the wide area monitoring and control system not only to control but also to monitoring in real time is proposed and the plan of integration interface with legacy system such as EMS for providing power system analysis base data effectively is suggested.

• The Journal of the Korea Contents Association
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• v.4 no.4
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• pp.99-106
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• 2004

This paper describes main characteristics of Grid Services based on OGSA and a service component for aggregating service data element. In order to build a Grid Service for SOA, it needs to consider a systematic approach from the high-level software architecture of a system that describes the main system components and their interactions. The purpose of this paper is to design and implement an extended service data aggregator service. To provide reliable aggregating service for service data elements, which is running under wide area environment like Internet, the aggregator service is operated asynchronously by notification mechanism.

• Journal of KIISE:Computing Practices and Letters
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• v.12 no.3
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• pp.160-169
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• 2006

The goal of this paper is to propose a way to register agents so that makes users or autonomousagents to find target agents more conveniently and efficiently. In order to achieve this goal, we first survey the key technologies such as UDDI, ebXML, FIPA DF. As the results, we designed a new agent legistry/repository system based on ebXML technologies. We introduce our agent/repository system for wide area network and describe how to use our system for agent registering and searching target agents for communications. Finally, we give an example to illustrate a typical scenario in which user receives the results from our proposed agent registry/repository system and evaluate its characteristics in terms of advantage.

• Fire Science and Engineering
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• v.30 no.1
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• pp.74-80
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• 2016

Ubiquitous computer technology (U technology) is continually, and the trend is moving towards the miniaturization of devices, cost reduction, performance enhancement, and intelligence. It is important to improve fire safety system by the application of advanced IT technologies. In this study, a vulnerable point in fire safety was selected for improvement by U technology. The structure of the whole system and a unit system was were designed. This system is divided into 5 parts: the U-fire protection facility management system, the U-fire safety information system, the U-fire safety education system, the U-fire response system, and the U-wide area fire safety management system. The prototype system was constructed in a real building to confirm the applicability of the system.

• IEIE Transactions on Smart Processing and Computing
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• v.4 no.4
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• pp.291-296
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• 2015

This paper describes the design of a high-speed comparator for high-speed automatic test equipment (ATE). The normal comparator block, which compares the detected signal from the device under test (DUT) to the reference signal from an internal digital-to-analog converter (DAC), is composed of a rail-to-rail first pre-amplifier, a hysteresis amplifier, and a third pre-amplifier and latch for high-speed operation. The proposed continuous comparator handles high-frequency signals up to 800MHz and a wide range of input signals (0~5V). Also, to compare the differences of both common signals and differential signals between two DUTs, the proposed differential mode comparator exploits one differential difference amplifier (DDA) as a pre-amplifier in the comparator, while a conventional differential comparator uses three op-amps as a pre-amplifier. The chip was implemented with $0.18{\mu}m$ Bipolar CMOS DEMOS (BCDMOS) technology, can compare signal differences of 5mV, and operates in a frequency range up to 800MHz. The chip area is $0.514mm^2$.

• Journal of Electrical Engineering and Technology
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• v.13 no.5
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• pp.1814-1820
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• 2018

State estimation of power systems has become vital in recent days of power operation and control. SCADA and EMS are intended for the state estimation and to communicate and monitor the systems which are operated at specified time. Although various methods are used we can achieve the better results by using PMU technique. On placing the PMU, operating time is reduced and making the performance reliable. In this paper, PMU placement is done in two ways. Those are 'optimal technique with pruning operation' and 'depth of unobservability' considering incomplete and complete observability of a network. By Depth of Unobservability Number of PMUs are reduced to attain Observability of the network. Proposed methods are tested on IEEE 14, 30, 57, SR-system and Sub systems (1, 2) with bus size of 270 and 444 buses. Along with achieving complete observability analysis, single PMU loss condition is also achieved.