• 한국컴퓨터정보학회논문지
• /
• 제9권3호
• /
• pp.171-175
• /
• 2004

본 논문은 이동 단말(mobile Node)의 핸드오프 발생시 끊김없는 핸드오프(seamless handoff)를 지원하기 위한 기법을 제안하고자 한다. 신호세기의 감소로 인한 핸드오프가 발생 가능한 상태일 때 이동단말은 기존의 CoA(Care-of Address) 외에 감지되는 신호를 통한 새로운 nCoA들을 만들어 자신의 영역을 담당하는 MAP(Mobility Anchor Point)에게 이들 nCoA에 대한 일시적인 바인딩 업데이트 tempBU(temporary Binding Update) 메시지를 보낸다. MAP은 전달받은 새로운 nCoA 주소를 포함한 바인딩 업데이트 메시지를 받아서 기존의 바인딩 정보 외에 새로운 바인딩 정보를 일시적으로 바인딩 캐쉬에 저장한다. 결국 이동단말이 새로운 액세스 라우터(nAR) 영역에 진입하여 확정된 바인딩 업데이트 메시지를 보낼 때까지 멀티캐스팅을 함으로써 끊김없는 핸드오프를 보장하는 기법을 제시한다.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제4권5호
• /
• pp.836-858
• /
• 2010

Web Services allow a user to integrate applications from different platforms and languages. Since mobile applications often run on heterogeneous platforms and conditions, Web Service becomes a popular solution for integrating with server applications. However, because of its verbosity, XML based SOAP messaging gives the possible overhead to the less powerful mobile devices. Based on the mobile client's behavior that it usually exchanges messages with Web Service continuously in a session, we design the Handheld Flexible Representation architecture. Our proposed architecture consists of three main components: optimizing message representation by using a data format language (Simple_DFDL), streaming communication channel to reduce latency and the Context-store to store context information of a session as well as redundant parts of the messages. In this paper, we focus on the Context-store and describe the architecture with the Context-store for improving the performance of mobile Web Service messaging. We verify our approach by conducting various evaluations and investigate the performance and scalability of the proposed architecture. The empirical results show that we save 40% of transit time between a client and a service by reducing the message size. In contrast to solutions for a single problem such as the compression or binarization, our architecture addresses the problem at a system level. Thus, by using the Context-store, we expect reliable recovery from the fault condition and enhancing interoperability as well as improving the messaging performance.

• 한국경영과학회지
• /
• 제24권2호
• /
• pp.95-108
• /
• 1999

The CDMA mobile system consists of several subsystems and each subsystem has many processing elements that handle voice messages and control messages for performing CDMA call processing functions through CDMA Interconnection Network(CIN). For assuring a high throughput and a short delay in the CIN, an efficient medium access control protocol should be provided. In this paper, we propose a new access control protocol of CIN for providing real time communications in CDMA mobile system. Also, we evaluate the delay performance of the proposed access control protocol and compare it with that of the existing access control protocol. Through a set of numerical examples, we show that our proposed protocol provides a better delay performance than the existing protocol.

• 디지털콘텐츠학회 논문지
• /
• 제10권1호
• /
• pp.115-120
• /
• 2009

메시지 페리 방법은 페리만이 분리된 네트워크 사이에서 메시지를 전달한다. 이 논문에서는 지연을 허용하는 분리된 네트워크에서 메시지 전달 지연시간을 줄이고 처리율을 증가시키기 위해 유한 버퍼의 페리와 이동 노드 모두가 메시지를 전달하는 새로운 방법을 제안한다. 우리는 메시지 전달 지연, 메시지 전달율 척도를 사용하여 기존의 메시지 페리 방법과 성능을 비교평가 한다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2003년도 통신소사이어티 추계학술대회논문집
• /
• pp.223-226
• /
• 2003

In this paper, we propose new agent discovery and route discovery schemes to support Mobile IP (MIP) in Ad Hoc networks with wireless backbone. The wireless backbone consisting of stationary wireless routers and Internet gateways (IGs) is a kind of wireless access network of IP-based core network. The proposed scheme utilizes favorable features of wireless backbone such as stable links and no energy constraints. In the agent discovery scheme, backbone-limited periodic Agent Advertisement (AA) and proxy-AA messages are used, which reduce network-wide broadcasting overhead caused by AA and Agent Solicitation messages and decentralize MIP processing overhead in IGs. In order to reduce delay time and control message overhead during route discovery far the destination outside Ad Hoc network, we propose a cache-based scheme which can be easily added to the conventional on-demand routing protocols. The proposed schemes can reduce control overhead during agent discovery and route discovery, and efficiently support MIP in Ad Hoc network with wireless backbone.

• 한국시뮬레이션학회:학술대회논문집
• /
• 한국시뮬레이션학회 1999년도 추계학술대회 논문집
• /
• pp.127-132
• /
• 1999

A mobile IP is proposed to support host mobility over the current Internet. One of the most important issues on the host mobility is location and routing schemes that allow mobile hosts to move effectively from one site to another. In a Mobile IP environment, frequent handoffs are likely to degrade the performance by minimizing the loss of datagrams during handoffs. The handoff scheme is using routing optimization and binding extension to improve the performance by minimizing the average transfer delay of messages and packet loss. Simulation details show the improvement of transport delays and packet loss rate.

• KSII Transactions on Internet and Information Systems (TIIS)
• /
• 제6권11호
• /
• pp.2849-2865
• /
• 2012

In order to block mobile junk messages automatically, many studies on spam filters have applied machine learning algorithms. Most previous research focused only on the accuracy rate of spam filters from the view point of the algorithm used, not on individual user's preferences. In terms of individual taste, the spam filters implemented on a mobile device have the advantage over spam filters on a network node, because it deals with only incoming messages on the users' phone and generates no additional traffic during the filtering process. However, a spam filter on a mobile phone has to consider the consumption of resources, because energy, memory and computing ability are limited. Moreover, as time passes an increasing number of feature words are likely to exhaust mobile resources. In this paper we propose a spam filter model distributed between a users' computer and smart phone. We expect the model to follow personal decision boundaries and use the uniform resources of smart phones. An authorized user's computer takes on the more complex and time consuming jobs, such as feature selection and training, while the smart phone performs only the minimum amount of work for filtering and utilizes the results of the information calculated on the desktop. Our experiments show that the accuracy of our method is more than 95% with Na$\ddot{i}$ve Bayes and Support Vector Machine, and our model that uses uniform memory does not affect other applications that run on the smart phone.

• 한국멀티미디어학회논문지
• /
• 제20권4호
• /
• pp.640-648
• /
• 2017

Sensors have limited resources in sensor networks, so efficient use of energy is important. In order to use the energy of the sensor node efficiently, researches applying mobile sink to the sensor network have been actively carried out. The sink node moves the sensor network, collects data from each sensor node, which spread the energy concentrated around the sink node, thereby extending the entire life cycle of the network. But, when the sink node moves, it requires a reset of the data transmission path, which causes a lot of control messages and delays. In this paper, we propose a CMS(Cluster-based Mobile Sink) method to support the movement of mobile sink in a cluster sensor environment. The proposed scheme minimizes an amount of control messages without resetting the routing paths of entire sensor networks by supporting the sink mobility path using the neighbor cluster list. And, it simplifies the routing path setup process by setting a single hop path between clusters without a gateway. The experiment results show that the proposed scheme has superior energy efficiency in processing and network structure, compared with existing clustering and mesh routing protocols.

• Child Health Nursing Research
• /
• 제25권3호
• /
• pp.303-311
• /
• 2019

Purpose: This study aimed to examine engagement and satisfaction with a mobile web-based education program (HiChart) among pregnant women. Methods: A cross-sectional descriptive study was conducted of 97 pregnant women hospitalized for obstetric care. Data were collected from October 1 to November 30, 2016, and were analyzed with descriptive statistics. Results: Among participants, 16.5% engaged fully with HiChart, while 43.3% engaged partially. The overall satisfaction with HiChart was high. Some main reasons for not engaging with the education were participants' unawareness of the text messages, lack of time, and poor internet connection. The participants suggested that more educational content needed to be covered, such as coping with infant emergencies and information about the neonatal intensive care unit. Conclusion: To increase pregnant women's engagement with mobile web-based education, efforts are needed to strengthen the system of sending text messages as part of mobile web-based education to all patients, to inform pregnant women that an educational web link was sent, and to encourage them to engage with mobile web-based education. Furthermore, it is essential to improve the HiChart service by providing educational content corresponding to users' needs.

• 한국콘텐츠학회논문지
• /
• 제13권4호
• /
• pp.8-16
• /
• 2013

U-Healthcare의 활성화를 위해 모바일 기기를 활용한 원격진료 및 진료지원에 대한 연구가 활발하다. 특히 원격처방시스템을 허용하는 의료법이 개정되면 모바일 처방시스템에 관한 연구는 급속도로 확산될 것이다. 그러나 모바일 앱은 모바일 플랫폼의 특성에 따라서 호환성이 떨어지는 특징을 가지므로, 플랫폼에 맞게 다시 개발해야 하는 제약사항을 가진다. 이러한 문제점을 보완하기 위해 이 논문에서는 모바일 표준 웹 개발 언어로 대두된 HLTML5와 자바스크립트 라이브러리인 jQuery Mobile을 이용하여 모바일 웹 처방 인터페이스를 설계한다. 또한, 기존의 병원정보시스템과의 자료 공유를 위해서 표준 프로토콜인 HL7을 기반으로 하는 메시지 형태로 변환하는 기능을 추가한다. HL7 메시지 송신을 통해 기존의 병원정보시스템과의 연동이 가능하도록 한다. 제안 시스템은 모바일 플랫폼에 독립적이고, 범용 컴퓨터에서도 호환성을 가지므로 다양한 환경에서 활용이 가능한 장점을 가진다.