• Journal of the Korea Society of Computer and Information
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• v.11 no.4 s.42
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• pp.165-174
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• 2006

As context aware service supports a process of context acquisition and reasoning, there are many studies to facilitate the implementation of context aware service. However, these studies have not supported efficiently a user or service mobility that should be supported necessarily in ubiquitous computing environment. Therefore, this study proposes a dynamic context aware service model which supports a dynamic management of context information, service retrieval and composition for interactions between services, and service mobility. Then we design a middleware based on this model and implement the middleware. As the middleware is implemented on the OSGi framework. it can have an interoperability between the devices such as computers, PDA, home appliances, and sensors, because of using the standard interface technologies like UPnP. Jini and so on.

• Proceedings of the Korea Information Processing Society Conference
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• 2008.05a
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• pp.871-874
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• 2008

이동성을 제공하기 위한 프로토콜 중 오랜 기간 많은 연구로 표준화가 된 Mobile IPv6 (MIPv6)가 있다. MIPv6는 호스트 기반 이동성 제공 프로토콜로서 이동 단말이 이동성에 필요한 시그널링을 직접수행한다. 한편, 최근에 표준화 작업이 진행 중인 Proxy Mobile IPv6 (PMIPv6)는 네트워크 기반 이동성 제공 프로토콜로서 이동 단말이 아닌 네트워크 자체에서 이동성을 제공한다. PMIPv6는 MIPv6에서 Home Agent와 같은 역할을 하는 Local Mobility Anchor 와 이동 단말이 수행하던 시그널링을 대신하는 Mobile Access Gateway를 정의하여 이동성을 제공한다. PMIPv6의 기본 동작 과정에 대한 표준화가 진행됨에 따라 프로토콜의 최적화에 대한 이슈가 부각되고 있다. Route Optimization은 이러한 최적화 이슈 중 하나로서 패킷 전송 시 최적화 된 경로를 설정하고 발생할 수 있는 전송 지연을 최소화하는 기법이다. 본 논문에서는 PMIPv6에서의 Route Optimization을 적용하기 위해 Liebesch 인터넷 드래프트에서 제안 한 기법의 동작 과정을 살펴보고 PMIPv6의 기본 전송 과정과 비교하여 그 성능을 분석하였다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.1
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• pp.135-141
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• 2018

In this paper, we describe design and implementation of optimal smart home control system. Recent developments in technologies such as sensors and communication have enabled the Internet of Things to control a wide range of objects, such as light bulbs, socket-outlet, or clothing. Many businesses rely on the launch of collaborative services between them. However, traditional IoT systems often support a single protocol, although data is transmitted across multiple protocols for end-to-end devices. In addition, depending on the manufacturer of the Internet of things, there is a dedicated application and it has a high degree of complexity in registering and controlling different IoT devices for the internet of things. ARIoT system, special marking points and edge extraction techniques are used to detect objects, but there are relatively low deviations depending on the sampling data. The proposed system implements an IoT gateway of object based on OneM2M to compensate for existing problems. It supports diverse protocols of end to end devices and supported them with a single application. In addition, devices were learned by using deep learning in the artificial intelligence field and improved object recognition of existing systems by inference and detection, reducing the deviation of recognition rates.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.12B
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• pp.1380-1386
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• 2009

In this paper, we propose a CQS(Calendar Queue Scheduler) architecture which was designed for processing multimedia and timing traffic in home network. With various characteristics of the increased traffic flowed in home such as VoIP, VOD, IPTV, and Best-efforts traffic, the needs of managing QoS(Quality of Service) are being discussed. Making a group regarding application or service is effective to guarantee successful QoS under the restricted circumstances. The proposed design is aimed for home gateway corresponding to the end points of receiver on end-to-end QoS and eligible for supporting multimedia traffic within restricted network sources and optimizing queue sizes. Then, we simulated the area for each module and each memory. The area for each module is referenced by NAND($2{\times}1$) Gate(11.09) when synthesizing with Magnachip 0.18 CMOS libraries through the Synopsys Design Compiler. We verified the portion of memory is 85.38% of the entire CQS. And each memory size is extracted through CACTI 5.3(a unit in mm2). According to the increase of the memory’sentry, the increment of memory area gradually increases, and defining the day size for 1 year definitely affects the total CQS area. In this paper, we discussed design methodology and operation for each module when designing CQS by hardware.

• Journal of KIISE:Information Networking
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• v.34 no.1
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• pp.62-72
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• 2007

Mobile Virtual Private Network (MVPN) provides VPN services without geographical restriction to mobile workers using mobile devices. Coexistence of Mobile IP (MIP) protocol for mobility and IPsec-based VPN technology are necessary in order to provide continuous VPN service to mobile users. However, Problems like registration failure or frequent IPsec tunnel re-negotiation occur when IPsec-based VPN Gateway (GW) and MIP are used together. In order to solve these problems, IETF proposes a mechanism which uses external home agent (x-HA) located external to the corporate VPN GW. In addition, based on the IETF proposal, a mechanism that assigns x-HA dynamically in the networks where MN is currently located was also proposed with the purpose to reduce handover latency as well as end-to-end delay. However, this mechanism has problems such as exposure of a session key for dynamic Mobility Security Association (MSA) or a long latency in case of the handover between different networks. In this paper, we propose a new MVPN protocol in order to minimize handover latency, enhance the security in key exchange, and to reduce data losses cause by handover. Through a course of simulation, the performance of proposed protocol is compared with the existing mechanism.

• Journal of KIISE
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• v.43 no.6
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• pp.710-717
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• 2016

Recently, several research studies on things abstraction framework have been proposed in order to implement the multi-service Internet of Things (IoT) system, where various IoT services share the thing devices. Distributed things abstraction has an IoT service duplication problem, which aggravates power consumption of mobile devices and network traffic. On the other hand, cloud server-centric things abstraction cannot cover real-time interactions due to long network delay. Fog server-centric things abstraction has limits in insufficient IoT interfaces. In this paper, we propose Smart Fog which is a fog server-centric things abstraction framework to resolve the problems of the existing things abstraction frameworks. Smart Fog consists of software modules to operate the Smart Gateway and three interfaces. Smart Fog is implemented based on IoTivity framework and OIC standard. We construct a smart home prototype on an embedded board Odroid-XU3 using Smart Fog. We evaluate the network performance and energy efficiency of Smart Fog. The experimental results indicate that the Smart Fog shows short network latency, which can perform real-time interaction. The results also show that the proposed framework has reduction in the network traffic of 74% and power consumption of 21% in mobile device, compared to distributed things abstraction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.11
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• pp.2083-2090
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• 2006

In an proposed Context-Aware SOA(Service Oriented Architecture) based OSGi(Open Service Gateway initiative) platform, Service provider manages relative kinds of services in an integrative basis from various sensors, puts each service in a SOAP (Simple Object access Protocol) message, and register thorn to the UDDI(Universal Description Discovery and Integration) server of service registry, service requester retrivel the specified kinds of services and call them to service provider. Recently most context-aware technologies for ubiquitous home network are mainly putting emphasis on RFID/USN and location-based technology. Because of this, service-oriented architecture researches have not been made enough. Under the environment of an OSGi service platform, various context-aware services are dynamically mapping from various sensors, new services are being offered for the asking of users, and existing services are changing. Accordingly, the data sharing between services provided, management of service life cycle, and the facilitation of service distribution are needed. Taking into considering all these factors, this study has suggested an Context-Aware SOA based eclipse SOA Tools Platform using OSGi platform that can transaction throughtput of more than 546 TPS of distributional Little's Law from ATAM(Architecture Tradeoff Analysis Method) while remaining stable other condition.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.3
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• pp.781-793
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• 2010

Recently, owing to the development of ubiquitous sensor network and mobile communication technologies, many studies on healthcare system are being carried out. In this paper, we have designed and implemented a mobile u-Healthcare system based on sensor network. The u-Healthcare system is composed of three components: wireless sensor network at home, healthcare center located at remote site, and gateway which relays sensing physiological signals to healthcare center. In order to measure patient's physiological signal three sensors are used: three channel ECG sensor, pulse oximeter, and blood pressure sensor. Each sensor is mounted on a mote which can send gathered signal to the base node using Zigbee communication protocol. Once the base node receives physiological signal from each sensor, the client in the base node transfers the signal to the healthcare center. The received physiological signal at the healthcare center is analyzed and processed using various algorithms. The processed results are compared to the standard healthcare database and appropriate treatment including dietetics and exercise cure would be sent to the patient as feedback using SMS message or healthcare center web site. Each patient can check and manage one's health state every day using the healthcare system and gain a recovery under the treatments from minor health problems.

• The KIPS Transactions:PartC
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• v.13C no.6 s.109
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• pp.691-700
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• 2006

To support context-aware services in ubiquitous computing environments, there are required dynamic context managing, context reasoning and context modeling technologies. In previous researches, context services are designed using context ontology used in context aware middleware. So, context service cannot change the context ontology in execution time. In this paper, we propose a hierarchical ontology-based context management model and design a context-aware middleware based on this model for supporting active application adaptability and reflecting users' requirements dynamically in contextual changes. It also provides efficient support for inferencing, interpreting, acquiring and discovering various contexts to build context-aware services and presents a resolution method for context conflict which is occurred in execution of service. As the middleware is implemented on the OSGi framework, it can cause interoperability among devices such as computers, PDAs, home appliances and sensors. It can also support the development and operation of context aware services, which are required in the ubiquitous computing environment.

• Journal of Advanced Navigation Technology
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• v.19 no.1
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• pp.85-90
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• 2015

In this paper, a novel Internet-of-things (IoT) based telecare system is proposed to provide high-quality care services to silver generations. It consists of various sensor nodes including activity sensors, wearable emergency pagers, emergency telephone as a home gateway, and a server as a telecare service platform. Especially, an activity index as a qualification method is presented to analyze the activities of daily living. By using the activity index, the daily/weekly/monthly activity information can be obtained, from which we infer the activity pattern, notice the abrupt change of the activity, and take appropriate actions in abnormal situations.