• 한국정보통신학회논문지
• /
• 제10권5호
• /
• pp.832-842
• /
• 2006

High-rate WPAN 은 CAT의 Time Slot 할당 스케줄링 방법을 정의 하고 있지 않다. 이에 CAT의 Time Slot 할당 스케줄링 방법 에 관한 많은 연구가 진행 중이다. 하지만 지금까지의 연구들은 Air Interface의 에러 요소의 미적용이나 특정 DEV의 기아 현상 등의 단점 등을 내포하고 있다. 이에 본 논문에서는 채널의 상태에 따른 우회 경로를 제공하여 채널 타임 할당 스케줄링 방법의 단점을 극복하는 알고리즘을 제안한다.

• 한국정보통신학회:학술대회논문집
• /
• 한국정보통신학회 2013년도 춘계학술대회
• /
• pp.938-940
• /
• 2013

원자력 발전소의 안전관리에 대한 관심이 높아짐에 따라, 관리를 위한 모니터링 시스템 개발의 필요성이 높아지고 있다. 또한 스마트폰, 스마트패드의 확산과 무선 네트워크의 진화가 스마트 혁명을 촉발하고 있으며, 삶의 변화 뿐 아니라, 모바일 중심으로 산업성장 및 인터넷 경제가 부상하고 있다. 이에 본 논문에서는 스마트 혁명 시대에 부응하기 위하여 전통 원자력 산업에 최신 스마트 기술을 융합한 방사선 안전관리 콘텐츠 시스템을 제안한다. 기본적인 영상 및 선량 데이터를 실시간으로 출력하며, 방사선 안전관리에 필요한 기본 모니터링 기능을 제공한다.

• 한국통신학회논문지
• /
• 제31권10B호
• /
• pp.900-908
• /
• 2006

본 논문에서는 이동성을 보장하면서 다양한 멀티미디어 서비스 및 컨텐츠를 지원하는 서비스들이 거의 동시에 상용화되는 상황에서 향후 이들 서비스의 시장경쟁구도가 어떻게 형성될 것인지에 대해 예측해 보고자 한다. 미래 시장경쟁구도 예측을 위해서 과거 정보통신사업에서 시장자료에 근거하여 판단하는 방법을 지양하고, 소비자 선호에 근거하는 선택확률모형을 적용하는 접근법을 시도함으로써 유사 서비스들의 경쟁양상을 보다 정확하게 분석할 수 있는 계기를 마련하였다. 분석결과, 서비스들간의 대체효과, 유인효과, 외부영향 요인에 따른 변화 양상 등을 예상할 수 있었고, 이들을 근거로 하여 기업전략 방향이나 정부정책 수립에 대해 전반적으로 나아갈 방향을 제시하였다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제7권3호
• /
• pp.425-445
• /
• 2013

The IEEE 802.11 compliant stations can transmit at multiple transmission rates. Selection of an appropriate transmission rate plays a significant role in determining the overall efficiency of a communication system. The technique which determines the channel state information and accordingly selects an appropriate transmission rate is called rate-adaptation protocol. The IEEE 802.11 standard does not provide standard specification for implementing a rate-adaptation protocol for its multi-rate capable wireless stations. Due to the lack of standard specification, there is a myriad of rate-adaptation protocols, proposed by industry and various research institutes. This paper surveys the existing rate-adaptation schemes, discusses various features which contribute significantly in the process of rate-adaptation, the timing constraints on such schemes, and the performance gains in terms of throughput, delay and energy efficiency; which can be gained by the use of rate-adaptation. The paper also discusses the implication of rate-adaptation schemes on the performance of overall communication and identifies existing research challenges in the design of rate-adaptation schemes.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제11권9호
• /
• pp.4242-4263
• /
• 2017

Multi-User Multiple-Input Multiple-Output (MU-MIMO) technology has recently attracted significant attention from academia and industry because of it is increasingly important role in improving networks' capacity and data rate. Moreover, MU-MIMO systems for the Fifth Generation (5G) have already been researched. High Quality of Service (QoS) and efficient operations at the Medium Access Control (MAC) layer have become key requirements. In this paper, we propose a downlink MU-MIMO MAC protocol based on adaptive Channel State Information (CSI) feedback (called MMM-A) for Wireless Local Area Networks (WLANs). A modified CSMA/CA mechanism using new frame formats is adopted in the proposed protocol. Specifically, the CSI is exchanged between stations (STAs) in an adaptive way, and a packet selection strategy which can guarantee a fairer QoS for scenarios with differentiated traffic is also included in the MMM-A protocol. We then derive the expressions of the throughput and access delay, and analyze the performance of the protocol. It is easy to find that the MMM-A protocol outperforms the commonly used protocols in terms of the saturated throughput and access delay through simulation and analysis results.

• 인터넷정보학회논문지
• /
• 제18권5호
• /
• pp.87-94
• /
• 2017

Due to the recent advances of IT industry, many companies and institutions have been used electronic documents rather than original paper copies. However, the characteristic of electronic document allows it to be readily damaged from proscribed copying, counterfeit, and falsification. These can cause the serious security problems for electronic documents. Conventional security methods for digital documents involve adding a separated image or marker, but these methods can reduce the readability of document. Therefore, we proposed a digital Jikin (Korean traditional stamp) which is normally used to identify the source or author of a document in asia. The proposed digital Jikin can preserve the readability of electronic document while protecting the document from proscribed copying, counterfeit, or falsification using image processing approach. In this paper, a digital Jikin application is designed and implemented under android platform and it converts the critical information of document onto the digital Jikin. The proposed digital Jikin contains important information in the boundary of Jikin not only about the author of documents or source, but also keywords, number of images, and many more. Therefore, the authenticity of document or whether the document has been altered or not by other person can be evaluated by the server. The proposed digital Jikin can be sent to a server through the wireless networks and can be stored using PHP and MySQL. We believe that the proposed method can offer the better and simple solution for strengthening the security of electronic document.

• 융합보안논문지
• /
• 제5권2호
• /
• pp.57-63
• /
• 2005

급속한 컴퓨터와 유 무선 인터넷의 발달로 인해 네트워크를 통한 정보의 교류가 활발해지고 있다. 또한 전자상거래와 관련된 산업의 규모가 커지면서 편리한 사용자 인증 시스템의 필요성이 요구되어 보안과 편리성을 갖춘 새로운 인증방식에 대한 연구가 체계적으로 진행되고 있다. 새로운 인증방식의 하나인 스마트카드는 높은 보안성과 기능성 및 편리성으로 인해 기존의 인증방식의 문제점을 극복하여 다목적 기능을 갖춘 하나의 카드로 대치될 것으로 전망된다. 본 논문에서는 스마트카드의 보안과 모든 분야에서 사용 가능한 하나의 원카드 시스템 구현에 대하여 제시하고자 한다.

• 한국컴퓨터정보학회논문지
• /
• 제20권12호
• /
• pp.53-59
• /
• 2015

In this paper, we developed a Hospital Information System in which the business process is formalized and a wire/wireless integrated solution is used. This system consists of the administration office program, the medical office program, the ward management program and the rounds management program. The administration office program can enroll and accept patients, issue and reissue the RFID card. The medical office program inputs a medical examination and treatment, outputs a diagnosis, requests a hospitalization, retrieves the record of a medical examination and treatment, assigns the corresponding examination room to the accepted patients, and updates the number of an waiting patient and a patient number according to the examination room on real time. The ward management program handles hospitalizations and leaving hospital, a nurse's note, and an isolation ward monitoring. The rounds management program handles a medical examination and treatment, and a leaving hospital using PDA. This developed system can be built at low cost and increase the quality of the medical services highly by making it automated the medical administration automation. Also the small number of the medical staffs can manage the inpatients efficiently by using the monitoring functions.

• 대한안전경영과학회지
• /
• 제9권6호
• /
• pp.155-162
• /
• 2007

Recently, retail store automation appliance market is changed with traditional POS systems techniques and RFID, radio POS system, and self checkout system, etc. in the foreign advanced distribution industry. Retailers and consumers require convenient POS system which can provide more functions and fast service. These requests bring to rapid evolution of various H/W and S/W corresponding with POS system. In this study with the POS systems and the RFID technology we develop core technology of movable u-POS system based on RFID that can use in large store. So we propose u-Cart system that can alternate the current shopping cart and POS terminal and that provide value added services to customer. As the result we present the configuration of u-Cart terminal device(WMDT : Wireless Mobile Data Terminal) including RFID reader module that can provide various information to consumer and some convenient client applications that are running in WMDT and u-POS administration service module.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 D
• /
• pp.2825-2827
• /
• 2000

In electric power industry. load balance has been one of the most fundamental and important management goals. Therefore. the strategy to achieve high quality load management now includes load balance besides the stabilization of electricity supply and quality management of electricity. Amongst many techniques of load management. direct load management has been actively studied and utilized to increase power facility and peak load suppression. Higher peak load situation is appeared during summer than during winter in Korea. and approximately 20% of the peak load is due to the load for air-conditioning. To cope with this peak load problem during summer KEPCO is performing a research project to develop a system to remotely control air-conditioning load using wireless communication. Currently, applicable facilities are limited to small-scale air-conditioning facility that has less than 2KW power capacity. This paper described the 1st year of efforts made in the study.