Soon Ju Kang

A three-tier middleware architecture supporting bidirectional location tracking of numerous mobile nodes under legacy WSN environment

Abstract In the mobile asset management services applicable to warehouse, hospital, etc. a low-cost and practical bidirectional location tracking of mobile asset is one of the most important technical issue must be solved. Due to the complexity and heavy traffic of the legacy location-awareness techniques, simultaneous locationing and tracking of numerous mobile nodes in real-time is not easy. To address this problem, we propose the three-tier middleware architecture called uMATI (ubiquitous Mobile Asset Tracking Infra). In the uMATI, all nodes (stationary and mobile) commonly use the IEEE 802.15.4 MAC protocol to guarantee the compatibility with the legacy wireless sensor network (WSN) despite of mobile-stationary nodes co-existence network. To solve the bidirectional tracking in spite of the free mobility of the numerous mobile nodes, we firstly suggest a simple bidirectional location protocol called BLIDx (bidirectional location ID exchange) and its implementation into both the mobile and stationary nodes. In addition, to prevent the traffic overflow due to the concentration of excessive mobile nodes into a single location, we propose adding a specially designed stationary node called virtual sink (VS) node and installing related middleware components into the node. Results from the experimental evaluation prove that the proposed architecture enhanced the practicability by effectively supporting the mobility and managing the traffic in the real-time mobile asset tracking applications.

Multi-thread based synchronization of locomotion control in snake robots

In this paper, we present an approach to control the locomotion of snake robot with concurrent programming model constructed using threads and semaphores. The multi-thread based concurrent programming model adds the flexibility to design and synchronize the movement of snake robots as compared with microcontroller and mechanical based approaches. We have designed a physical snake robot using LEGO sensors and actuator blocks and the wave motion of the snake robot is generated by multi-thread based concurrent programming under RT-Linux. The different robot movements in a desired direction along with different types of snake movements are achieved using angle sensors.

Real-time event kernel architecture for home-network gateway set-top-box (HNGS)

This paper discusses a software architecture for a set-top-box that serves as intermediary connecting home networks to the Internet. As the major design challenge in developing the software is supporting inherent real-time requirements of home networks and home Internet connectivity simultaneously, the software is designed to integrate both real-time service and home Internet connectivity into one software framework.

CORBA based core middleware architecture supporting seamless interoperability between standard home network middlewares

The current paper presents a CORBA based core middleware architecture for supporting seamless interoperability in an IEEE1394-based home network. To support CORBA on top of an IEEE139-based home network, a CORBA programming platform is designed and implemented without any loss of the real-time properties of the IEEE1394 protocol. To customize the real-time CORBA properties using the IEEE1394 protocol, first, a specially designed device driver for the IEEE1394 adaptor is developed based on an RT-Linux kernel. On top of the device driver, an IEEE1394 ORB is also designed and implemented to support CORBA. The proposed ORB consists of two components. One is the IEEE1394 asynchronous ORB according to the GIOP specification of CORBA to support interoperability with other ORBS, such as IIOP, and the other is the IEEE1394 isochronous ORB to retain the real-time properties of the IEEE1394 protocol. The performance of the proposed CORBA based core middleware platform is verified based on a prototype home network test-bed.

An event channel-based embedded software architecture for developing telemetric and teleoperation systems on the WWW

We propose a new embedded software architecture for developing telemetric and teleoperation systems on the WWW (World Wide Web) that is called WTTS (Web-based Telemetric and Teleoperation System). First of all, we define the general functions of WTTSs which should support not only local real time service such as sensor data gathering and actuator controlling but also remote Web based services such as alarm reporting and remote commanding of the devices. According to the functions, we design the event channel based on priority queue to perform the services under hard or soft constraints for real time processing. By adopting the proposed concept, we can effectively merge Web service tasks as the remote service and hard real time tasks as the local service into a software architecture within limited computing resources of embedded real time systems. In order to verify the proposed architecture, we built a Web based vending machine as a prototype by using LEGO Dacta and implemented the proposed architecture under the Java environment in a RTOS.

A multi-agent architecture for intelligent home network service using tuple space model

The major design challenge to realize intelligent home network services is organizing distributed and heterogeneous home devices effectively. In order to meet the design challenge, an agent space based multi-agent architecture is considered. In addition, we also proposed a new middleware on the IEEE1394 network to support reliable communication between agent spaces.

IEEE 802.15.4 MAC-based Location-ID Exchange Protocol for Realizing Micro-Cell Connectionless Location- Awareness Services

We propose ID-exchange protocol for Connectionless Location-Awareness Service (CLAS) to locate mobile nodes in indoor sensor network. When adapting location-awareness service to sensor network, the target system must be designed in accordance with various metrics which reflect the system requirement. We especially consider sustainability of the existing service which has been provided for its original purpose, such as environmental monitoring. The detailed meaning of sustainability here is that, even if location-awareness service is newly added to the existing service, the system must be assured to retain a stable network condition, and to deal with newly caused traffic properly. The CLAS ID-exchange protocol is especially designed for fixture and mobile nodes communication to achieve these properties. The protocol operates on 802.15.4 MAC layer to make mobile node work independently of the procedure to build routing table of fixture node, so a stable routing condition can be achieved even if there are many mobile nodes. Moreover, the dedicated frequency channel is assigned only for this protocol, so that traffic caused by location-awareness service can be distributed to another channel. A real system adapting the protocol was implemented to monitor fire and authorities’ positions. We verified the overhead and elapsed time for location-awareness. The result shows the proposed protocol has a high performance in detecting speed, traffic distribution, and stability of overall network.

Fully Distributed Monitoring Architecture Supporting Multiple Trackees and Trackers in Indoor Mobile Asset Management Application

A tracking service like asset management is essential in a dynamic hospital environment consisting of numerous mobile assets (e.g., wheelchairs or infusion pumps) that are continuously relocated throughout a hospital. The tracking service is accomplished based on the key technologies of an indoor location-based service (LBS), such as locating and monitoring multiple mobile targets inside a building in real time. An indoor LBS such as a tracking service entails numerous resource lookups being requested concurrently and frequently from several locations, as well as a network infrastructure requiring support for high scalability in indoor environments. A traditional centralized architecture needs to maintain a geographic map of the entire building or complex in its central server, which can cause low scalability and traffic congestion. This paper presents a self-organizing and fully distributed indoor mobile asset management (MAM) platform, and proposes an architecture for multiple trackees (such as mobile assets) and trackers based on the proposed distributed platform in real time. In order to verify the suggested platform, scalability performance according to increases in the number of concurrent lookups was evaluated in a real test bed. Tracking latency and traffic load ratio in the proposed tracking architecture was also evaluated.

ROOM-BRIDGE: Vertically Configurable Network Architecture and Real-Time Middleware for Interoperability between Ubiquitous Consumer Devices in the Home

This research focuses on the development of a generic home network architecture and related middleware for supporting interoperability between ubiquitous consumer devices and computing devices in the home. In order to build a practical home network, design criteria are discussed, including real-time constraints and interoperability between heterogeneous protocols. As a result, a vertically configurable home network architecture and real-time middle-ware, called ROOM-BRIDGE, are presented that meet the design criteria. ROOM-BRIDGE is specially designed and implemented using an IEEE1394 backbone network to provide the proposed network architecture with a guarantee of seamless and reliable communication between heterogeneous subnetworks and ubiquitous devices in the home. The performance of the proposed network architecture and ROOM-BRIDGE was verified by prototype implementation and testing using a home network test bed

Remote service discovery and binding architecture for soft real-time QoS in indoor location-based service

Indoor location-based service (LBS) is generally distinguished from web services that have no physical location and user context. In particular, various resources have dynamic and frequent mobility in indoor environments. In addition, an indoor LBS includes numerous service lookups being requested concurrently and frequently from several locations, even through a network infrastructure requiring high scalability in indoor environments. The traditional centralized LBS approach needs to maintain a geographical map of the entire building or complex in its central server, which can cause low scalability and traffic congestion. This paper presents a self-organizing and fully distributed indoor LBS platform with regional cooperation among devices. A service lookup algorithm based on the proposed distributed architecture searches for the shortest physical path to the nearest service resource. A continuous service binding mechanism guarantees a probabilistic real-time QoS regardless of dynamic and frequent mobility in a soft real-time system such as an indoor LBS. Performance evaluation of the proposed algorithm and platform is compared to the traditional centralized architecture in the experimental evaluation of scalability and real test bed environments.