• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2005년도 추계종합학술대회
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• pp.31-34
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• 2005

In this paper, we proposed a MAC protocol which can be used in power line communications(PLC). In the power line communication network, the data signal cannot travel long distance because of a serious attenuation. Consequently, we need to have a number of repeaters (amplifiers) in order to recover the signal power, which causes flooding problem in the network The proposed MAC protocol uses polling concept and solves the flooding problem in the power line communication network. The proposed protocol can be applied to power line communication networks for automatic power distribution control system. A mathematical analysis has been carried out to estimate the performance of the proposed protocol.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2005년도 춘계학술대회 논문집
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• pp.1013-1017
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• 2005

This paper proposes an effective algorithm, P-DCF(Polling DCF) to satisfy real-time requirements in the industrial environments, based on 802.11 DCF protocols. Theoretical analysis and actual experiments are carried out, which shows that the proposed P-DCF brings several benefits: 1) it reduces the time delay for frame transmission 2)it guarantees bounded upper limit of maximum transmission delay 3) it maintains fairness

• Asian Journal for Public Opinion Research
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• 제2권1호
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• pp.52-70
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• 2014

Gathering polling items about China and Japan from 1937 to 2011, we examine how Americans think about these two powerful East Asian countries. Our study investigates American attitudes from two perspectives. First, we analyze the content of polling items asked in the US about China and Japan to track changes in salient issues over a period of over 60 years. Second, by tracking repeated items, we show how American attitudes toward China and Japan have changed over time, both in long-term general favorability, and shorter-term perception of geopolitical, ideological, and economic threat in response to historical events.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2000년도 제15차 학술회의논문집
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• pp.107-107
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• 2000

This paper focuses on a method to connect mobile devices such as mobile robot, ACV and UTC with Profibus network. In this paper, the IEEE 802.11 wireless LAN is used for wireless extension of Frofibus, and four major issues are introduced to implement the wireless extended Profibus; First, the integration method between Profibus and IEEE 802.11 is introduced. Second, the implementation method of gateway is proposed. Three, the virtual polling mode algorithm is developed for satisfaction of real-time characteristics required in industrial network. Finally, we implement a experimental model, and carried out the performance analysis of wireless extended Profibus. This results show that wireless extended Profibus is suitable to industrial network such as automated container terminal.

• Smart Structures and Systems
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• 제21권2호
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• pp.225-234
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• 2018

E-Health allows you to supersede the central patient wireless healthcare system. Wireless Body Sensor Network (WBSN) is the first phase of the e-Health system. In this paper, we aim to understand e-Health architecture and configuration, and attempt to minimize energy consumption and latency in transmission routing protocols during restrictive latency in data delivery of WBSN phase. The goal is to concentrate on polling protocol to improve and optimize the routing time interval and schedule communication to reduce energy utilization. In this research, two types of network models routing protocols are proposed - elemental and clustering. The elemental model improves efficiency by using a polling protocol, and the clustering model is the extension of the elemental model that Destruct Supervised Decision Tree (DSDT) algorithm has been proposed to solve the time interval conflict transmission. The simulation study verifies that the proposed models deliver better performance than the existing BSN protocol for WBSN.

• 전자공학회논문지A
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• 제29A권7호
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• pp.10-18
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• 1992

In this paper, a simulation model for scope and filter parameters in CMIS/CMIP, OSI management protocol, has been discussed and the suitable scope type was represented by analyzing optimal polling time in network management system, queue size and response time. Scope and filter parameters in MGet, M-Set, M-Action, and =M-Delete services provide a scheme to select some managed objects, and the results are largely varied according to a scope type requested and the outcome of filtering. It has been simulated each scope type and all scope type mixed in a network by varying the offered load and a polling time. On the same time, the response time, queue size of the managing system and a delay time have been measured. As a results, the suitable scope type and polling time enhancing the network performance on the OSI network management is proposed.

• Communications for Statistical Applications and Methods
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• 제6권3호
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• pp.881-892
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• 1999

In this paper we consider a polling system with two classes of stations; high priority and low priority. High priority stations are polled more frequently than low priority stations. We derive an exact and explicit formula for computing the mean waiting times for a message when the arrival processes are batch Poisson. In general the formula requires to solve two sets of simultaneous equations By specializing them to the case of two priority classes we greatly reduce the number equations and provide a simple formula for mean waiting times. We apply the results to a data communication processing system and show that the overall mean waiting time can be reduced by using priority polling.

• 한국컴퓨터정보학회논문지
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• 제20권8호
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• pp.23-28
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• 2015

TPSN(Timing-sync Protocol for Sensor Networks), the representative of time synchronization protocol for WSN(wireless sensor networks), was developed to provide higher synchronization accuracy and energy efficiency. So, TPSN's approach has been referenced by so many other WSN synchronization schemes till now. However, TPSN has a collision problem due to simultaneous transmission among competing nodes, which causes more network convergence delay for a network-wide synchronization. A Polling-based scheme for TPSN is proposed in this paper. The proposed scheme not only shortens network-wide synchronization time of TPSN, but also reduce collision traffic which lead to needless power consumption. The proposed scheme's performance has been evaluated and compared with an original scheme by simulation. The results are shown to be better than the original algorithm used in TPSN.

• 한국정보과학회논문지:데이타베이스
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• 제37권1호
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• pp.22-32
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• 2010

최근 무선인터넷 기술의 발달과 응용의 확산으로 인하여 위치정보를 이용한 위치기반 서비스 형태는 매우 다양해지고 있으며, 국내외 시장에서 급속히 확산되고 있다. 위치기반 서비스의 기본적인 정보인 위치정보는 이동체 데이터로 관리되며, 현재까지 다양한 방법의 이동체 데이터 관리방법이 제시되고 있다. 위치기반 서비스 중 특정지역에 진입하거나 벗어날 경우에 자동으로 정보를 제공하는 위치기반 경보 서비스는 현재 주요한 위치기반 서비스 중의 하나로서 주목을 받고 있다. 위치기반 경보서비스를 제공하기 위해서는 대상이 되는 이동체의 위치정보를 주기적으로 획득해야 한다. 이러한 방법은 이동성을 가지는 수많은 이동체의 위치정보를 지속적으로 획득해야 하며 이는 심각한 시스템 부하를 초래할 수 있다. 현재까지 연구되고 있는 이동체를 위한 위치획득방법은 모바일 사용자들이 동적이고 불규칙적인 이동속도 및 이동패턴을 보일 때 만족스러운 성능을 보여주지 못하고 있다. 이에 본 논문에서는 위치기반 경보서비스를 제공하기 위해 대용량의 위치정보를 획득함에 있어서, 이동 체외 이동패턴을 이용하여 불필요한 위치정보 획득회수를 줄임으로써 시스템의 부하를 줄이는 효율적인 이동체 획득방법을 제안하였다. 또한 기존의 이동체 획득방법들과의 성능 비교를 통하여 본 논문에서 제안한 이동체 획득방법의 성능이 우수함을 알 수 있었다.

• Communications for Statistical Applications and Methods
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• 제5권3호
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• pp.809-817
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• 1998

In this paper we consider a polling system where the token is passed according to a general service order table. We derive an exact and explicit formula to compute the mean waiting time for a message when the arrivals of messages are modeled by batch Poisson processes.