• ETRI Journal
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• v.34 no.1
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• pp.55-65
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• 2012

E-voting is expected to offer prominent advantages over traditional voting methods. Advantages include faster tallying, greater accuracy, prevention of void ballots, and lower cost. However, many experts express concerns about the potential for large-scale fraud. Recently, many paper based end-to-end (E2E) voter verifiable systems providing individual verifiability and universal verifiability have been proposed. These systems, unlike previous voting systems, are used in polling booths and without access to trusted computing devices at the time of voting. In this paper, we propose a practical and secure E2E voter verifiable system using a paper receipt based on cryptographic technologies.

• Proceedings of the Korean Institute of Intelligent Systems Conference
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• 2000.11a
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• pp.413-418
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• 2000

For Pneumatic system control, we need a data transmission system with high speed and high realibility for information interchange between main computer and solenoid valves and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid valves. In addition we developed a communication protocol for construction of RS-485 based multidrop network, and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. The field test results show that, even under high noise environment, the data transmission of 375Kbps rate is possible up to 1,000m without using repeater. In addition, the system developed in this research is proved to be used easily for extension of a communication network because of its module structure.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.2
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• pp.194-201
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• 2010

This paper discuss a performance evaluation of the synchronization algorithm for hybrid networks in industrial environments. The proposed algorithms minimizes synchronization errors which were caused from channel, Propagation, and frequency delays. The modified RBS and offset synchronization methods can be operated by adjustment parameters. The differential BP (Back-off Period) adjustment can synchronize the local time of each node with master node's time in hybrid networks. For the performance analysis, the data transmission time between the wired and wireless devices are investigated. The experimental results show the performance evaluations in terms of the polling service time and an average end-to-end delay.

• Journal of Communications and Networks
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• v.14 no.1
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• pp.34-39
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• 2012

Collisions between tags greatly reduce the identification speed in radio frequency identification (RFID) systems and increase communication overhead. In particular for an active RFID system, tags are powered by small batteries, and a large number of re-transmissions caused by collisions can deteriorate and exhaust the tag energy which may result in missing tags. An efficient collision-free arbitration protocol for active RFID systems is proposed in this paper. In this protocol, a new mechanism involving collision detection, collision avoidance, and fast tag access is introduced. Specifically, the pulse burst duration and busy-tone-detection delay are introduced between the preamble and data portion of a tag-to-reader (T-R) frame. The reader identifies tag collision by detecting pulses and transmits a busy tone to avoid unnecessary transmission when collision occurs. A polling process is then designed to quickly access the collided tags. It is shown that the use of the proposed protocol results in a system throughput of 0.612, which is an obvious improvement when compared to the framed-slotted ALOHA (FSA) arbitration protocol for ISO/IEC 18000-7 standard. Furthermore, the proposed protocol greatly reduces communication overhead, which leads to energy conservation.

• The KIPS Transactions:PartC
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• v.16C no.5
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• pp.661-668
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• 2009

The Extended real-time Polling Service (ErtPS) is proposed tosupport QoS of VoIP service with silence suppression which generates variable size data packets in IEEE 802.16e systems. If the silence is suppressed, VoIP should support Comfort Noise Generation (CNG) which generates comfort noise for receiver's auditory sense to notify the status of connection to the user. CNG mode in silent-period generates a data with lower bit rate at long packet transmission intervals in comparison with talk-spurt. Therefore, if the ErtPS, which is designed to support service flows that generate data packets on a periodic basis, is applied to silent-period, resources of the uplink are used inefficiently. In this paper, we proposed the Improved ErtPS algorithm for efficient resource utilization of the silent-period in VoIP traffic supporting CNG. In the proposed algorithm, the base station allocates bandwidth depending on the status of voice at the appropriate interval by havingthe user inform the changes of voice status. The Improved ErtPS utilizes the Cannel Quality Information Channel (CQICH) which is an uplink subchannel for delivering quality information of channel to the base station on a periodic basis in 802.16e systems. We evaluated the performance of proposed algorithm using OPNET simulator. We validated that proposed algorithm improves the bandwidth utilization of the uplink and packet transmission latency

• Proceedings of the Korean Information Science Society Conference
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• 2001.10c
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• pp.73-75
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• 2001

분산 시스템은 원거리에 위치한 자원들을 하나의 시스템으로 통합하여 여러 가지 장점을 제공한다. 하지만 시스템의 규모가 커짐에 따라서 관리자 노드와 관리 대상 노드간의 빈번한 상호작용에 의해서 전체적인 시스템의 성능저하가 발생할 수 있다. 에이전트를 사용한 방법으로 중앙 집중형 관리 방법의 폴링(polling)애 따른 문제점을 해결하였으나 에이전트 사용에 있어서도 에이전트가 이동하는 파견방법에 따라서 성능의 차이가 발생할 수 있다. 즉, 에이전트를 파견하는 관리 대상 노드의 지역 계산 시간에 따라서 관리자 노드에서의 전체적인 응답시간과 네트워크의 부하가 달라질 수 있다. 따라서 , 본 논문에서는 에이전트가 관리 대상 노드에서의 지역 계산 시간에 따라 현재 작업중인 노드의 다음 노드에 에이전트의 복제(Cloning)를 통해 새로운 에이전트를 파견하여 관리자 노드에서의 응답시간과 네트워크 부하를 줄일 수 있는 방법을 제시하고 기존의 모델과의 평가를 응답시간과 네트워크 부하 측면에서 비교, 평가하였다.

• 제어로봇시스템학회:학술대회논문집
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• 2001.10a
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• pp.150.2-150
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• 2001

For pneumatic system control, we need a data transmission system with high speed and reliability for information interchange between main computer and I/O devices. This paper presents a set of design techniques for a data communication system that is mainly used for pneumatic system control. For this purpose, we first designed hardware modules for an interface between central control module and local node that handles the operation of solenoid valves. In addition, we developed a communication protocol for construction of RS-485 based multi-drop network, and this protocol is basically designed with a kind of polling technique. Finally we evaluated performance of the developed system. The field test results show that, even under high noise environment, the data transmission of 375Kbps rate is ...

• Proceedings of the Korean Information Science Society Conference
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• 1999.10c
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• pp.268-270
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• 1999

국내외를 불문하고 네트워크 환경의 대중화로 인한 그 수요의 증가로 네트워크 기술 자체에 대한 이해는 물론이며, 네트워크에 연결된 수 많은 장비들에 대한 트래픽 문제의 해결과 효율적인 관리가 필수적이다. 중앙집중형 NMS는 네트워크에 연결된 수 많은 NE들을 구성하고 제어하기 위하여 대부분의 네트워크에서 SNMP를 이용하고 있으나, Manager와 Agent 들의 계속적인 Polling과 정보교환은 오히려 네트웍 트래픽을 증가시키는 역할을 하고 있다. 그리하여 최근에 SNMPv2를 이용한 분산형 망관리 시스템이 도입되고 있다. 따라서 본 논문은 망 관리 시스템의 내부적 부하인 SNMP의 네트워크 트래픽을 중앙집중형과 분산형 망관리 시스템으로 구분하여 시스템 다이내믹스 모델링 기법과 시스템 다이내믹스 시뮬레이션 툴인 STELLA를 이용하여 네트워크 트래픽 패턴을 분석하여, 망 관리 시스템 구축시 적절한 요소의 가감을 통해 네트워크 트래픽을 줄이고, 효율적인 망관리 시스템을 구축하는데 그 목적이 있다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.67-69
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• 2000

분산 시스템은 원거리에 위치한 자원들을 하나의 시스템으로 통합하여 여러 가지 장점을 제공한다. 하지만 시스템의 규모가 커짐에 따라서 관리자 노드와 관리 대상 노드간의 빈번한 상호작용에 의해서 전체적인 시스템의 성능저하가 발생할 수 있다. 에이전트를 사용한 방법으로 중앙 집중형 관리 방법의 폴링(polling)에 따른 문제점을 해결하였으나 에이전트 사용에 있어서도 에이전트가 이동하는 파견방법에 따라서 성능의 차이가 발생할 수 있다. 즉, 에이전트를 파견하는 관리 대상 노드의 지역 계산 시간에 따라서 관리자 노드에서의 전체적인 응답시간과 네트워크의 부하가 달라질 수 있다. 따라서, 본 논문에서는 에이전트가 관리 대상 노드에서의 지역 계산 시간에 따라 현재 작업중인 노드의 다음 노드로 새로운 에이전트를 파견하여 관리자 노드에서의 응답시간과 네트워크 부하를 줄일 수 있는 방법을 제시하고 기존의 모델과의 평가를 응답시간과 네트워크 부하 측면에서 비교, 평가하였다.

• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2005.11a
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• pp.213-216
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• 2005

Recently, energy depleting problem have risen seriously. Many studies of daylight responsive dimming system for saving of lighting energy in office buildings have been done actively. Most of studies are focused on the accuracy. However if the variation of dimming levels is changed too often, occupants would feel uncomfortable. First, illuminance changes which occupants couldn't detect are studied through analyzing foreign studies. Second, workplan illuminance from daylight in each sky condition is measured. Because the dimming level In daylight responsive dimming system is dependent on the workplan illuminance from daylight. In conclusion, the most appropriate polling periods to daylight responsive dimming system for occupant's visual comfort was determined.